1IPSEC.CONF(5) Executable programs IPSEC.CONF(5)
2
6 ipsec.conf - IPsec configuration and connections
7
9 The ipsec.conf file specifies most configuration and control
10 information for the Libreswan IPsec subsystem. (The major exception is
11 secrets for authentication; see ipsec.secrets(5).) Its contents are not
12 security-sensitive. Configurations can be added using this
13 configuration file or by using ipsec whack directly. This means that
14 technically, the ipsec.conf file is optional, but a few warnings might
15 show up when this file is missing.
16 ipsec.conf is a text file, consisting of one or more sections. White
18 space followed by # followed by anything to the end of the line is a
19 comment and is ignored, as are empty lines that are not within a
20 section.
21 A line that contains include and a file name, separated by white space,
23 is replaced by the contents of that file, preceded and followed by
24 empty lines. If the file name is not a full pathname, it is considered
25 to be relative to the directory that contains the including file. Such
26 inclusions can be nested. Only a single filename may be supplied, and
27 it may not contain white space, but it may include shell wildcards (see
28 sh(1)); for example:
29 include /etc/ipsec.d/*.conf
31 The intention of the include facility is mostly to permit keeping
33 information on connections, or sets of connections, separate from the
34 main configuration file. This permits such connection descriptions to
35 be changed, copied to the other security gateways involved, etc.,
36 without having to constantly extract them from the configuration file
37 and then insert them back into it. Note also the also and alsoflip
38 parameters (described below) which permit splitting a single logical
39 section (e.g. a connection description) into several distinct sections.
40 The first significant line of the file may specify a version of this
42 specification for backwards compatibility with freeswan and openswan.
43 It is ignored and unused. For compatibility with openswan, specify:
44 version 2
46 A section begins with a line of the form:
48 type name
50 where type indicates what type of section follows, and name is an
52 arbitrary name that distinguishes the section from others of the same
53 type. (Names must start with a letter and may contain only letters,
54 digits, periods, underscores, and hyphens.) All subsequent non-empty
55 lines that begin with white space are part of the section; comments
56 within a section must begin with white space too. There may be only one
57 section of a given type with a given name.
58 Lines within the section are generally of the form
60 parameter=value
62 (note the mandatory preceding white space). There can be white space on
64 either side of the =. Parameter names follow the same syntax as section
65 names, and are specific to a section type. Unless otherwise explicitly
66 specified, no parameter name may appear more than once in a section.
67 An empty value stands for the system default value (if any) of the
69 parameter, i.e. it is roughly equivalent to omitting the parameter line
70 entirely. A value may contain white space only if the entire value is
71 enclosed in double quotes ("); a value cannot itself contain a double
72 quote, nor may it be continued across more than one line.
73 Numeric values are specified to be either an “integer” (a sequence of
75 digits) or a “decimal number” (sequence of digits optionally followed
76 by `.' and another sequence of digits).
77 There is currently one parameter that is available in any type of
79 section:
80 also
82 the value is a section name; the parameters of that section are
83 appended to this section, as if they had been written as part of
84 it. The specified section must exist, must follow the current one,
85 and must have the same section type. (Nesting is permitted, and
86 there may be more than one also in a single section, although it is
87 forbidden to append the same section more than once.) This allows,
88 for example, keeping the encryption keys for a connection in a
89 separate file from the rest of the description, by using both an
90 also parameter and an include line. (Caution, see BUGS below for
91 some restrictions.)
92 alsoflip
94 can be used in a conn section. It acts like an also that flips the
95 referenced section's entries left-for-right.
96 Parameter names beginning with x- (or X-, or x_, or X_) are reserved
98 for user extensions and will never be assigned meanings by IPsec.
99 Parameters with such names must still observe the syntax rules (limits
100 on characters used in the name; no white space in a non-quoted value;
101 no newlines or double quotes within the value). All other as-yet-unused
102 parameter names are reserved for future IPsec improvements.
103 A section with name %default specifies defaults for sections of the
105 same type. For each parameter in it, any section of that type that does
106 not have a parameter of the same name gets a copy of the one from the
107 %default section. There may be multiple %default sections of a given
108 type, but only one default may be supplied for any specific parameter
109 name. %default sections may not contain also or alsoflip parameters.
110 Currently there are two types of section: a config section specifies
112 general configuration information for IPsec, while a conn section
113 specifies an IPsec connection.
114
116 A conn section contains a connection specification, defining a network
117 connection to be made using IPsec. The name given is arbitrary, and is
118 used to identify the connection to ipsec_auto(8) Here's a simple
119 example:
120 conn snt
123 left=10.11.11.1
124 leftsubnet=10.0.1.0/24
125 leftnexthop=172.16.55.66
126 leftsourceip=10.0.1.1
127 right=192.168.22.1
128 rightsubnet=10.0.2.0/24
129 rightnexthop=172.16.88.99
130 rightsourceip=10.0.2.1
131 keyingtries=%forever
132 A note on terminology... In automatic keying, there are two kinds of
134 communications going on: transmission of user IP packets, and
135 gateway-to-gateway negotiations for keying, rekeying, and general
136 control. The data path (a set of “IPsec SAs”) used for user packets is
137 herein referred to as the “connection”; the path used for negotiations
138 (built with “ISAKMP SAs”) is referred to as the “keying channel”.
139 To avoid trivial editing of the configuration file to suit it to each
141 system involved in a connection, connection specifications are written
142 in terms of left and right participants, rather than in terms of local
143 and remote. Which participant is considered left or right is arbitrary;
144 IPsec figures out which one it is being run on based on internal
145 information. This permits using identical connection specifications on
146 both ends. There are cases where there is no symmetry; a good
147 convention is to use left for the local side and right for the remote
148 side (the first letters are a good mnemonic).
149 Many of the parameters relate to one participant or the other; only the
151 ones for left are listed here, but every parameter whose name begins
152 with left has a right counterpart, whose description is the same but
153 with left and right reversed.
154 Parameters are optional unless marked “(required)”
156 CONN PARAMETERS: GENERAL
158 The following parameters are relevant to IKE automatic keying. Unless
159 otherwise noted, for a connection to work, in general it is necessary
160 for the two ends to agree exactly on the values of these parameters.
161 keyexchange
163 method of key exchange; the default and currently the only accepted
164 value is ike
165 hostaddrfamily
167 the address family of the hosts; currently the accepted values are
168 ipv4 and ipv6. The default is to detect this based on the IP
169 addresses specified or the IP addresses resolved, so this option is
170 not needed, unless you specify hostnames that resolve to both IPv4
171 and IPv6. This option used to be named connaddrfamily but its use
172 was broken so it was obsoleted in favour or using the new
173 hostaddrfamily and clientaddrfamily.
174 clientaddrfamily
176 the address family of the clients (subnets); currently the accepted
177 values are ipv4 and ipv6. The default is to detect this based on
178 the network IP addresses specified or the network IP addresses
179 resolved, so this option is not needed, unless you specify names
180 that resolve to both IPv4 and IPv6.
181 type
183 the type of the connection; currently the accepted values are
184 tunnel (the default) signifying a host-to-host, host-to-subnet, or
185 subnet-to-subnet tunnel; transport, signifying host-to-host
186 transport mode; passthrough, signifying that no IPsec processing
187 should be done at all; drop, signifying that packets should be
188 discarded; and reject, signifying that packets should be discarded
189 and a diagnostic ICMP returned.
190 left
192 (required) the IP address or DNS hostname of the left participant's
193 public-network interface, Currently, IPv4 and IPv6 IP addresses are
194 supported. If a DNS hostname is used, it will be resolved to an IP
195 address on load time, and whenever a connection is rekeying or
196 restarting (such as when restarted via a DPD failure detection).
197 This allows one to use a DNS hostname when the endpoint is on a
198 dynamic IP address.
199 There are several magic values. If it is %defaultroute, left will
201 be filled in automatically with the local address of the
202 default-route interface (as determined at IPsec startup time); this
203 also overrides any value supplied for leftnexthop. (Either left or
204 right may be %defaultroute, but not both.) The value %any signifies
205 an address to be filled in (by automatic keying) during
206 negotiation. The value %opportunistic signifies that both left and
207 leftnexthop are to be filled in (by automatic keying) from DNS data
208 for left's client. The value can also contain the interface name,
209 which will then later be used to obtain the IP address from to fill
210 in. For example %ppp0. The values %group and %opportunisticgroup
211 makes this a policy group conn: one that will be instantiated into
212 a regular or opportunistic conn for each CIDR block listed in the
213 policy group file with the same name as the conn.
214 If using IP addresses in combination with NAT, always use the
216 actual local machine's (NATed) IP address, and if the remote (eg
217 right=) is NATed as well, the remote's public (not NATed) IP
218 address. Note that this makes the configuration no longer
219 symmetrical on both sides, so you cannot use an identical
220 configuration file on both hosts.
221 leftsubnet
223 private subnet behind the left participant, expressed as
224 network/netmask (actually, any form acceptable to
225 ipsec_ttosubnet(3)); Currently, IPv4 and IPv6 ranges are supported.
226 if omitted, essentially assumed to be left/32, signifying that the
227 left end of the connection goes to the left participant only
228 It supports two magic shorthands vhost: and vnet:, which can list
230 subnets in the same syntax as virtual-private. The value %priv
231 expands to the networks specified in virtual-private. The value %no
232 means no subnet. A common use for allowing roadwarriors to come in
233 on public IPs or via accepted NATed networks from RFC1918 is to use
234 leftsubnet=vhost:%no,%priv. The vnet: option can be used to allow
235 RFC1918 subnets without hardcoding them. When using vnet the
236 connection will instantiate, allowing for multiple tunnels with
237 different subnets.
238 leftsubnets
240 specify multiple private subnets behind the left participant,
241 expressed as { networkA/netmaskA, networkB/netmaskB [...] } If
242 both a leftsubnets= and rightsubnets= are defined, all combinations
243 of subnet tunnels will be established as IPsec tunnels. You cannot
244 use leftsubnet= and leftsubnets= together. For examples see
245 testing/pluto/multinet-*. Be aware that when using spaces as
246 separator, that the entire option value needs to be in double
247 quotes.
248 leftvti
250 the address/mask to configure on the VTI interface when
251 vti-interface is set. It takes the form of network/netmask
252 (actually, any form acceptable to ipsec_ttosubnet(3)); Currently,
253 IPv4 and IPv6 ranges are supported. This option is often used in
254 combination with routed based VPNs.
255 leftaddresspool
257 address pool from where the IKEv1 ModeCFG or IKEv2 server can
258 assign IP addresses to clients. When configured as a server, using
259 leftxauthserver=yes this option specifies the address pool from
260 which IP addresses are taken to assign the clients. The syntax of
261 the address pool specifies a range (not a CIDR) for IPv4 and CIDR
262 for IPv6, in the following syntax:
263 rightaddresspool=192.168.1.100-192.168.1.200 or
264 rightaddresspool=2001:db8:0:3:1::/97 Generally, the
265 rightaddresspool= option will be accompanied by
266 rightxauthclient=yes, leftxauthserver=yes and leftsubnet=0.0.0.0/0
267 option.
268 When leftaddresspool= is specified, the connection may not specify
270 either leftsubnet= or leftsubnets=. Address pools are fully
271 allocated when the connection is loaded, so the ranges should be
272 sane. For example, specifying a range
273 rightaddresspool=10.0.0.0-11.0.0.0 will lead to massive memory
274 allocation. Address pools specifying the exact same range are
275 shared between different connections. Different addresspools should
276 not be defined to partially overlap.
277 leftprotoport
279 allowed protocols and ports over connection, also called Port
280 Selectors. The argument is in the form protocol, which can be a
281 number or a name that will be looked up in /etc/protocols, such as
282 leftprotoport=icmp, or in the form of protocol/port, such as
283 tcp/smtp. Ports can be defined as a number (eg. 25) or as a name
284 (eg smtp) which will be looked up in /etc/services. A special
285 keyword %any can be used to allow all ports of a certain protocol.
286 The most common use of this option is for L2TP connections to only
287 allow l2tp packets (UDP port 1701), eg: leftprotoport=17/1701.
288 To filter on specific icmp type and code, use the higher 8 bits for
290 type and the lower 8 bits for port. For example, to allow icmp echo
291 packets (type 8, code 0) the 'port' would be 0x0800, or 2048 in
292 decimal, so you configure leftprotoport=icmp/2048. Similarly, to
293 allow ipv6-icmp Neighbour Discovery which has type 136 (0x88) and
294 code 0(0x00) this becomes 0x8800 or in decimal 34816 resulting in
295 leftprotoport=ipv6-icmp/34816 .
296 Some clients, notably older Windows XP and some Mac OSX clients,
298 use a random high port as source port. In those cases
299 rightprotoport=17/%any can be used to allow all UDP traffic on the
300 connection. Note that this option is part of the proposal, so it
301 cannot be arbitrarily left out if one end does not care about the
302 traffic selection over this connection - both peers have to agree.
303 The Port Selectors show up in the output of ipsec eroute and ipsec
304 auto --status eg:"l2tp":
305 193.110.157.131[@aivd.libreswan.org]:7/1701...%any:17/1701 This
306 option only filters outbound traffic. Inbound traffic selection
307 must still be based on firewall rules activated by an updown
308 script. The variables $PLUTO_MY_PROTOCOL, $PLUTO_PEER_PROTOCOL,
309 $PLUTO_MY_PORT, and $PLUTO_PEER_PORT are available for use in
310 updown scripts. Older workarounds for bugs involved a setting of
311 17/0 to denote any single UDP port (not UDP port 0). Some clients,
312 most notably OSX, uses a random high port, instead of port 1701 for
313 L2TP.
314 leftnexthop
316 next-hop gateway IP address for the left participant's connection
317 to the public network; defaults to %direct (meaning right). If the
318 value is to be overridden by the left=%defaultroute method (see
319 above), an explicit value must not be given. If that method is not
320 being used, but leftnexthop is %defaultroute, the next-hop gateway
321 address of the default-route interface will be used. The magic
322 value %direct signifies a value to be filled in (by automatic
323 keying) with the peer's address. Relevant only locally, other end
324 need not agree on it.
325 leftsourceip
327 the IP address for this host to use when transmitting a packet to
328 the other side of this link. Relevant only locally, the other end
329 need not agree. This option is used to make the gateway itself use
330 its internal IP, which is part of the leftsubnet, to communicate to
331 the rightsubnet or right. Otherwise, it will use its nearest IP
332 address, which is its public IP address. This option is mostly used
333 when defining subnet-subnet connections, so that the gateways can
334 talk to each other and the subnet at the other end, without the
335 need to build additional host-subnet, subnet-host and host-host
336 tunnels. Both IPv4 and IPv6 addresses are supported.
337 leftupdown
339 what "updown" script to run to adjust routing and/or firewalling
340 when the status of the connection changes (default ipsec _updown).
341 May include positional parameters separated by white space
342 (although this requires enclosing the whole string in quotes);
343 including shell metacharacters is unwise. An example to enable
344 routing when using the XFRM stack, one can use:
345 leftupdown="ipsec _updown --route yes"
347 To disable calling an updown script, set it to the empty string, eg
349 leftupdown="" or leftupdown="%disabled".
350 See ipsec_pluto(8) for details. Relevant only locally, other end
352 need not agree on it.
353 leftcat
355 Whether to perform Client Address Translation ("CAT") when using
356 Opportunistic IPsec behind NAT. Accepted values are no (the
357 default) and yes. This option should only be enabled on the special
358 Opportunistic IPsec connections, usually called "private" and
359 "private-or-clear". When set, this option causes the given
360 addresspool IP from the remote peer to be NATed with iptables. It
361 will also install an additional IPsec SA policy to cover the
362 pre-NAT IP. See the Opportunistic IPsec information on the
363 libreswan website for more information and examples.
364 leftfirewall
366 This option is obsolete and should not used anymore.
367 If one or both security gateways are doing forwarding firewalling
369 (possibly including masquerading), and this is specified using the
370 firewall parameters, tunnels established with IPsec are exempted from
371 it so that packets can flow unchanged through the tunnels. (This means
372 that all subnets connected in this manner must have distinct,
373 non-overlapping subnet address blocks.) This is done by the default
374 updown script (see ipsec_pluto(8)).
375 The implementation of this makes certain assumptions about firewall
377 setup, and the availability of the Linux Advanced Routing tools. In
378 situations calling for more control, it may be preferable for the user
379 to supply his own updown script, which makes the appropriate
380 adjustments for his system.
381 CONN PARAMETERS: AUTOMATIC KEYING
383 The following parameters are relevant to automatic keying via IKE.
384 Unless otherwise noted, for a connection to work, in general it is
385 necessary for the two ends to agree exactly on the values of these
386 parameters.
387 auto
389 what operation, if any, should be done automatically at IPsec
390 startup; currently-accepted values are add (signifying an ipsec
391 auto --add), ondemand (signifying that plus an ipsec auto
392 --ondemand), start (signifying that plus an ipsec auto --up), and
393 ignore (also the default) (signifying no automatic startup
394 operation), and keep (signifying an add plus an attempt to keep the
395 connection up once the remote peer brought it up). See the config
396 setup discussion below. Relevant only locally, other end need not
397 agree on it (but in general, for an intended-to-be-permanent
398 connection, both ends should use auto=start to ensure that any
399 reboot causes immediate renegotiation).
400 The option ondemand used to be called route
402 authby
404 how the two security gateways should authenticate each other; the
405 default value is rsasig,ecdsa which allows ECDSA with SHA-2 and RSA
406 with SHA2 or SHA1. To limit this further, there are the options of
407 ecdsa for ECDSA digital signatures using SHA-2, rsa-sha2 for
408 RSASSA-PSS digital signatures based authentication with SHA2-256,
409 rsa-sha2_384 for RSASSA-PSS digital signatures based authentication
410 with SHA2-384, rsa-sha2_512 for RSASSA-PSS digital signatures based
411 authentication with SHA2-512, rsa-sha1 for RSA-PKCSv1.5 digital
412 signatures based authentication with SHA1, secret for shared
413 secrets (PSK) authentication, secret|rsasig for either, never if
414 negotiation is never to be attempted or accepted (useful for
415 shunt-only conns), and null for null-authentication.
416 If asymmetric authentication is requested, IKEv2 must be enabled,
418 and the options leftauth= and rightauth= should be used instead of
419 authby.
420 For IKEv1, SHA2 based signatures are not defined and ECDSA is not
422 implemented, so the default authby= value is rsa-sha1. Using
423 authby=rsasig results in only rsa-sha1 as well. For IKEv2, using
424 authby=rsasig means using rsa-sha2_512, rsa-sha2_384, rsa-sha2_256
425 and rsa-sha1, where rsa-sha1 will used only if RFC 7427 is not
426 supported by the peer.
427 As per RFC 8221, authby=rsa-sha1 is only supported in the old
429 style, meaning RSA-PKCSv1.5. The SHA2 variants are only supported
430 for the new style of RFC 7427, so authby=rsa-sha2 will use the new
431 style. The default authby= will remove rsa-sha1 in the near future.
432 It is strongly recommended that if certificates are used, the
433 certificates and the authby= signature methods used are the same,
434 as it increases interoperability and keeps the authentication of
435 everything within one digital signature system.
436 Digital signatures are superior in every way to shared secrets.
438 Especially IKEv1 in Aggressive Mode is vulnerable to offline
439 dictionary attacks and is performed routinely by at least the NSA
440 on monitored internet traffic globally. The never option is only
441 used for connections that do not actually start an IKE negotiation,
442 such as type=passthrough connections. The auth method null is used
443 for "anonymous opportunistic IPsec" and should not be used for
444 regular pre-configured IPsec VPNs.
445 ike
447 IKE encryption/authentication algorithm to be used for the
448 connection (phase 1 aka ISAKMP SA or IKE SA). If this option is not
449 set, the builtin defaults will be used. This is the preferred
450 method, and allows for gradual automatic updates using the same
451 configuration. Some distributions, such as Fedora and RHEL/CentOS,
452 use a System Wide Crypto Policy that sets the default ike= (and
453 esp=) lines. Specifying your own ike= line means overriding all
454 these system or software recommended defaults, but can be necessary
455 at times. Note that libreswan does not support using a PRF
456 algorithm that is different from the INTEGRITY (hash) algorithm by
457 design.
458 The format is "cipher-hash;modpgroup, cipher-hash;modpgroup, ..."
460 Any omitited option will be filled in with all allowed default
461 values. Multiple proposals are separated by a comma. If an ike=
462 line is specified, no other received proposals will be accepted
463 than those specified on the IKE line. Some examples are
464 ike=3des-sha1,aes-sha1, ike=aes, ike=aes_ctr, ike=aes_gcm256-sha2,
465 ike=aes128-md5;modp2048, ike=aes256-sha2;dh19,
466 ike=aes128-sha1;dh22, ike=3des-md5;modp1024,aes-sha1;modp1536.
467 IKEv2 allows combining elements into a single proposal. These can
469 be specified by using the + symbol. An example is:
470 ike=aes_gcm+chacha20_poly1305;dh14+dh19,aes+3des-sha2+sha1;dh14.
471 Note that AEAD algorithms (aes_gcm, aes_ccm, chacha20_poly1305) and
472 non-AEAD algorithms (aes, 3des) cannot be combined into a single
473 proposal. To support aes and aes_gcm, two proposals separated by a
474 comma must be used.
475 The default IKE proposal depends on the version of libreswan used.
477 It follow the recommendations of RFC4306, RFC7321 and as of this
478 writing their successor draft documents RFC4306bis and RFC7321bis.
479 As for libreswan 3.32, SHA1 and MODP1536(dh5) are still allowed per
480 default for backwards compatibility, but 3DES and MODP1024(dh2) are
481 not allowed per default. As of libreswan 4.x, modp1024(dh2) support
482 is no longer compiled in at all. For IKEv2, the defaults include
483 AES, AES-GCM, DH14 and stronger, and SHA2. The default key size is
484 256 bits. The default AES_GCM ICV is 16 bytes.
485 Note that AES-GCM is an AEAD algorithm, meaning that it performs
487 encryption+authentication in one step. This means that AES-GCM must
488 not specify an authentication algorithm. However, for IKE it does
489 require a PRF function, so the second argument to an AEAD algorithm
490 denotes the PRF. So ike=aes_gcm-sha2 means propose AES_GCM with
491 SHA2 as the prf. Note that for phase2alg, there is no prf, so
492 AES-GCM is specified for ESP as esp=aes_gcm-null. The AES-GCM and
493 AES-CCM algorithms support 8,12 and 16 byte ICV's. These can be
494 specified using a postfix, for example aes_gcm_a (for 8), aes_gcm_b
495 (for 12) and aes_gcm_c (for 16). The default (aes_gcm without
496 postfix) refers to the 16 byte ICV version. It is strongly
497 recommended to NOT use the 8 or 12 byte versions of GCM or CCM.
498 These versions are NOT included in the default and will be removed
499 in a future version, following the recommendation of RFC 8247 or it
500 successor.
501 Weak algorithms are regularly removed from libreswan. Currently,
503 1DES and modp768(DH1) have been removed and modp1024(DH2) has been
504 disabled at compile time. Additionally, MD5 and SHA1 will be
505 removed within the next few years. Null encryption is available,
506 and should only be used for testing or benchmarking purposes.
507 Please do not request for insecure algorithms to be re-added to
508 libreswan. IKEv1 has been disabled per default, and will soon no
509 longer be compiled in by default.
510 For all Diffie-Hellman groups, the "dh" keyword can be used instead
512 of the "modp" keyword. For example ike=3des-sha1;dh19.
513 Diffie-Hellman groups 19,20 and 21 from RFC-5903 are supported.
514 Curve25519 from RFC-8031 is supported as "dh31". Curve448 and GOST
515 DH groups are not yet supported in libreswan because these are not
516 supported yet in the NSS crypto library.
517 Diffie-Hellman groups 22, 23 and 24 from RFC-5114 are implemented
519 but not compiled in by default. These DH groups are extremely
520 controversial and MUST NOT be used unless forced (administratively)
521 by the other party. This is further documented in RFC 8247, but the
522 summary is that it cannot be proven that these DH groups do not
523 contain a cryptographic trapdoor (a backdoor by the USG who
524 provided these primes without revealing the seeds and generation
525 process used).
526 The modp syntax will be removed in favour of the dh syntax in the
528 future
529 phase2
531 Sets the type of SA that will be produced. Valid options are: esp
532 for encryption (the default), ah for authentication only.
533 The very first IPsec designs called for use of AH plus ESP to offer
535 authentication, integrity and confidentiality. That dual protocol
536 use was a significant burden, so ESP was extended to offer all
537 three services, and AH remained as an auth/integ. The old mode of
538 ah+esp is no longer supported in compliance with RFC 8221 Section
539 4. Additionally, AH does not play well with NATs, so it is strongly
540 recommended to use ESP with the null cipher if you require
541 unencrypted authenticated transport.
542 phase2alg
544 This option is alias to esp.
545 sha2-truncbug
547 The default ESP hash truncation for sha2_256 is 128 bits. Some
548 IPsec implementations (Linux before 2.6.33, some Cisco (2811?)
549 routers) implement the draft version which stated 96 bits. If a
550 draft implementation communicates with an RFC implementation, both
551 ends will reject encrypted packets from each other.
552 This option enables using the draft 96 bits version to interop with
554 those implementations. Currently the accepted values are no, (the
555 default) signifying default RFC truncation of 128 bits, or yes,
556 signifying the draft 96 bits truncation.
557 Another workaround is to switch from sha2_256 to sha2_128 or
559 sha2_512.
560 ms-dh-downgrade
562 Whether to allow a downgrade of DiffieHellman group during rekey
563 (using CREATE_CHILD_SA). Microsoft Windows (at the time of writing,
564 Feb 2018) defaults to using the very weak modp1024 (DH2). This can
565 be changed using a Windows registry setting to use modp2048 (DH14).
566 However, at rekey times, it will shamelessly use modp1024 again and
567 the connection might fail. Setting this option to yes (and adding
568 modp1024 proposals to the ike line) this will allow this downgrade
569 attack to happen. This should only be used to support Windows that
570 feature this bug. Currently the accepted values are no, (the
571 default) or yes.
572 dns-match-id
574 Whether to perform an additional DNS lookup and confirm the remote
575 ID payload with the DNS name in the reverse DNS PTR record.
576 Accepted values are no (the default) or yes. This check should be
577 enabled when Opportunistic IPsec is enabled in a mode that is based
578 on packet triggers (on-demand) using IPSECKEY records in DNS. Since
579 in that case the IKE daemon pluto does not know the remote ID, it
580 only knows the remote IP address, this option forces it to confirm
581 the peer's proposed ID (and thus its public/private key) with its
582 actual IP address as listed in the DNS. This prevents attacks where
583 mail.example.com's IP address is taken over by a neighbour machine
584 with a valid web.example.com setup. This check is not needed for
585 certificate based Opportunistic IPsec, as "mail.example.com"s
586 certificate does not have an entry for "web.example.com". It is
587 also not needed for DNS server triggered Opportunistic IPsec, as in
588 that case the IKE daemon pluto is informed of both the IP address,
589 and the hostname/public key.
590 require-id-on-certificate
592 When using certificates, check whether the IKE peer ID is present
593 as a subjectAltName (SAN) on the peer certificate. Accepted values
594 are yes (the default) or no. This check should only be disabled
595 when intentionally using certificates that do not have their peer
596 ID specified as a SAN on the certificate. These certificates
597 violate RFC 4945 Section 3.1 and are normally rejected to prevent a
598 compromised host from assuming the IKE identity of another host.
599 The SAN limits the IDs that the peer is able to assume.
600 ppk
602 EXPERIMENTAL: Post-quantum preshared keys (PPKs) to be used.
603 Currently the accepted values are propose or yes (the default),
604 signifying we propose to use PPK for this connection; insist,
605 signifying we allow communication only if PPK is used for key
606 derivation; never or no, signifying that PPK should not be used for
607 key derivation. PPKs can be used in connections that allow only
608 IKEv2. In libreswan that would mean that ikev2 option must have
609 value insist. (currently based on draft-fluhrer-qr-ikev2, not
610 raft-ietf-ipsecme-qr-ikev2-00)
611 nat-ikev1-method
613 NAT Traversal in IKEv1 is negotiated via Vendor ID options as
614 specified in RFC 3947. However, many implementations only support
615 the draft version of the RFC. Libreswan sends both the RFC and the
616 most common draft versions (02, 02_n and 03) to maximize
617 interoperability. Unfortunately, there are known broken
618 implementations of RFC 3947, notably Cisco routers that have not
619 been updated to the latest firmware. As the NAT-T payload is sent
620 in the very first packet of the initiator, there is no method to
621 auto-detect this problem and initiate a workaround.
622 This option allows fine tuning which of the NAT-T payloads to
624 consider for sending and processing. Currently the accepted values
625 are drafts, rfc, both (the default) and none. To interoperate with
626 known broken devices, use nat-ikev1-method=drafts. To prevent the
627 other end from triggering IKEv1 NAT-T encapsulation, set this to
628 none. This will omit the NAT-T payloads used to determine NAT,
629 forcing the other end not to use encapsulation.
630 esp
632 Specifies the algorithms that will be offered/accepted when
633 negotiating a a Child SA. The general syntax is:
634 ESP = PROPOSAL[,PROPOSAL...]
636 PROPOSAL = ENCRYPT_ALGS[-INTEG_ALGS[-DH_ALGS]]
637 ENCRYPT_ALGS = ENCRYPT_ALG[+ENCRYPT_ALG...]
638 INTEG_ALGS = INTEG_ALG[+INTEG_ALG...]
639 DH_ALGS = DH_ALG[+DH_ALG...]
640 During startup, ipsec_pluto(8) will log all supported ESP
643 algorithms.
644 Specifying the DH algorithms explicitly is not recommended. When
646 PFS is enabled, and the DH algorithms are omitted, each PROPOSAL
647 will automatically include the DH algorithm negotiated during the
648 IKE exchange.
649 AEAD algorithms such as AES_GCM and AES_CCM no not require a
651 separate integrity algorithm. For example esp=aes_gcm256 or
652 esp=aes_ccm.
653 For instance:
655 esp=aes_gcm,aes128+aes256-sha2_512+sha2_256-dh14+dh19
657 esp=aes128-sha2_512-dh14+dh19
658 If not specified, a secure set of defaults will be used. The
661 program:
662 ipsec algparse esp=...
664 can be used to query these defaults.
667 ah
669 A comma separated list of AH algorithms that will be
670 offered/accepted when negotiating the Child SA. The general syntax
671 is:
672 AH = PROPOSAL[,PROPOSAL...]
674 PROPOSAL = INTEG_ALGS[-DH_ALGS]
675 INTEG_ALGS = INTEG_ALG[+INTEG_ALG...]
676 DH_ALGS = DH_ALG[+DH_ALG...]
677 During startup, ipsec_pluto(8) will log all supported AH
680 algorithms.
681 Specifying the DH algorithms explicitly is not recommended. When
683 PFS is enabled, and the DH algorithms are omitted, each PROPOSAL
684 will automatically include the DH algorithm negotiated during the
685 IKE exchange.
686 The default is not to use AH. If for some (invalid) reason you
688 still think you need AH, please use esp with the null encryption
689 cipher instead.
690 For instance:
692 ah=sha2_256+sha2_512
694 ah=sha2_256+sha2_512-dh14+dh19
695 If not specified, a secure set of defaults will be used. The
698 program:
699 ipsec algparse ah=...
701 can be used to query these defaults.
704 fragmentation
706 Whether or not to allow IKE fragmentation. Valid values are yes,
707 (the default), no or force.
708 IKEv1 fragmentation capabilities are negotiated via a well-known
710 private vendor id. IKEv2 fragmentation support is implemented using
711 RFC 7383. If pluto does not receive the fragmentation payload, no
712 IKE fragments will be sent, regardless of the fragmentation=
713 setting. When set to yes, IKE fragmentation will be attempted on
714 the first re-transmit of an IKE packet of a size larger then 576
715 bytes for IPv4 and 1280 bytes for IPv6. If fragmentation is set to
716 force, IKE fragmentation is used on initial transmits of such sized
717 packets as well. When we have received IKE fragments for a
718 connection, pluto behaves as if in force mode.
719 ikepad
721 Whether or not to pad IKEv1 messages to a multiple of 4 bytes.
722 Valid values are yes, (the default) and no.
723 IKE padding is allowed in IKEv1 but has been known to cause
725 interoperability issues. The ikepad= option can be used to disable
726 IKEv1 padding. This used to be required for some devices (such as
727 Checkpoint in Aggressive Mode) that reject padded IKEv1 packets. A
728 bug was fixed in libreswan 3.25 that applied wrong IKE padding in
729 XAUTH, so it is suspected that Checkpoint padding issue bas been
730 resolved. And this option should not be needed by anyone. In IKEv2,
731 no padding is allowed, and this option has no effect. If you find a
732 device that seems to require IKE padding, please contact the
733 libreswan developers. This option should almost never be enabled
734 and might be removed in a future version.
735 ikev2
737 Whether to use IKEv2 (RFC 7296) or IKEv1 (RFC 4301). Currently the
738 accepted values are yes (the default), signifying only IKEv2 is
739 accepted, or no, signifying only IKEv1 is accepted. Previous
740 versions allowed the keywords propose or permit that would allow
741 either IKEv1 or IKEv2, but this is no longer supported. The permit
742 option is interpreted as no and the propose option is interpreted
743 as yes. Older versions also supported keyword insist which is now
744 interpreted as yes.
745 mobike
747 Whether to allow MOBIKE (RFC 4555) to enable a connection to
748 migrate its endpoint without needing to restart the connection from
749 scratch. This is used on mobile devices that switch between wired,
750 wireless or mobile data connections. Current values are no (the
751 default) or yes, Only connection acting as modecfgclient will allow
752 the initiator to migrate using mobike. Only connections acting as
753 modecfgserver will allow clients to migrate.
754 VTI and MOBIKE might not work well when used together.
756 esn
758 Whether or not to enable Extended Sequence Number (ESN) for the
759 IPsec SA. This option is only implemented for IKEv2. ESN is
760 typically used for very high-speed links (10Gbps or faster) where
761 the standard 32 bit sequence number is exhausted too quickly,
762 causing IPsec SA's rekeys to happen too often. Accepted values are
763 either (the default), yes and no. If either is specified as an
764 initiator, the responder will make the choice. As a responder, if
765 either is received, yes is picked.
766 If replay-window is set to 0, ESN is disabled as some (most?) IPsec
768 stacks won't support ESN in such a configuration.
769 decap-dscp
771 Enable decapsulating the Differentiated Services Code Point (DSCP,
772 formerly known as Terms Of Service (TOS)) bits. If these bits are
773 set on the inner (encrypted) IP packets, these bits are set on the
774 decrypted IP packets. Acceptable values are no (the default) or
775 yes. Currently this feature is only implemented for the Linux XFRM
776 stack.
777 nopmtudisc
779 Disable Path MTU discovery for the IPsec SA. Acceptable values are
780 no (the default) or yes. Currently this feature is only implemented
781 for the Linux XFRM stack.
782 narrowing
784 IKEv2 (RFC5996) Section 2.9 Traffic Selector narrowing options.
785 Currently the accepted values are no, (the default) signifying no
786 narrowing will be proposed or accepted, or yes, signifying IKEv2
787 negotiation may allow establishing an IPsec connection with
788 narrowed down traffic selectors. This option is ignored for IKEv1.
789 There are security implications in allowing narrowing down the
791 proposal. For one, what should be done with packets that we hoped
792 to tunnel, but cannot. Should these be dropped or send in the
793 clear? Second, this could cause thousands of narrowed down Child
794 SAs to be created if the conn has a broad policy (eg 0/0 to 0/0).
795 One possible good use case scenario is that a remote end (that you
796 fully trust) allows you to define a 0/0 to them, while adjusting
797 what traffic you route via them, and what traffic remains outside
798 the tunnel. However, it is always preferred to setup the exact
799 tunnel policy you want, as this will be much clearer to the user.
800 sareftrack
802 Set the method of tracking reply packets with SArefs when using an
803 SAref compatible stack. Currently only the mast stack supports
804 this. Acceptable values are yes (the default), no or conntrack.
805 This option is ignored when SArefs are not supported. This option
806 is passed as PLUTO_SAREF_TRACKING to the updown script which makes
807 the actual decisions whether to perform any iptables/ip_conntrack
808 manipulation. A value of yes means that an IPSEC mangle table will
809 be created. This table will be used to match reply packets. A value
810 of conntrack means that additionally, subsequent packets using this
811 connection will be marked as well, reducing the lookups needed to
812 find the proper SAref by using the ip_conntrack state. A value of
813 no means no IPSEC mangle table is created, and SAref tracking is
814 left to a third-party (kernel) module. In case of a third party
815 module, the SArefs can be relayed using the statsbin= notification
816 helper.
817 nic-offload
819 Set the method of Network Interface Controller (NIC) hardware
820 offload for ESP/AH packet processing. Acceptable values are auto
821 (the default), yes or no. This option is separate from any CPU
822 hardware offload available and is currently only available on Linux
823 4.13+ using the XFRM IPsec stack, when compiled with the options
824 CONFIG_XFRM_OFFLOAD, CONFIG_INET_ESP_OFFLOAD and
825 CONFIG_INET6_ESP_OFFLOAD. The auto option will attempt to
826 auto-detect the presence of kernel and hardware support, and then
827 automatically mark the IPsec SA for hardware offloading. One vendor
828 supporting this offload method is Mellanox.
829 leftid
831 how the left participant should be identified for authentication;
832 defaults to left. Can be an IP address or a fully-qualified domain
833 name which will be resolved. If preceded by @, the value is used as
834 a literal string and will not be resolved. To support opaque
835 identifiers (usually of type ID_KEY_ID, such as used by Cisco to
836 specify Group Name, use square brackets, eg rightid=@[GroupName].
837 The magic value %fromcert causes the ID to be set to a DN taken
838 from a certificate that is loaded. Prior to 2.5.16, this was the
839 default if a certificate was specified. The magic value %none sets
840 the ID to no ID. This is included for completeness, as the ID may
841 have been set in the default conn, and one wishes for it to default
842 instead of being explicitly set. The magic value %myid stands for
843 the current setting of myid. This is set in config setup or by
844 ipsec_whack(8)), or, if not set, it is the IP address in
845 %defaultroute (if that is supported by a TXT record in its reverse
846 domain), or otherwise it is the system's hostname (if that is
847 supported by a TXT record in its forward domain), or otherwise it
848 is undefined.
849 When using certificate based ID's, one need to specify the full
851 RDN, optionally using wildcard matching (eg CN='*'). If the RDN
852 contains a comma, this can be masked using a comma (eg OU='Foo,,
853 Bar and associates')
854 leftrsasigkey
856 the left participant's public key for RSA signature authentication,
857 in RFC 2537 format using ipsec_ttodata(3) encoding. The magic value
858 %none means the same as not specifying a value (useful to override
859 a default). The value %dnsondemand (the default) means the key is
860 to be fetched from DNS at the time it is needed. The value
861 %dnsonload means the key is to be fetched from DNS at the time the
862 connection description is read from ipsec.conf; currently this will
863 be treated as %none if right=%any or right=%opportunistic. The
864 value %dns is currently treated as %dnsonload but will change to
865 %dnsondemand in the future. The identity used for the left
866 participant must be a specific host, not %any or another magic
867 value. The value %cert will load the information required from a
868 certificate defined in %leftcert and automatically define leftid
869 for you. Caution: if two connection descriptions specify different
870 public keys for the same leftid, confusion and madness will ensue.
871 leftcert
873 If you are using leftrsasigkey=%cert this defines the certificate
874 nickname of your certificate in the NSS database. This can be on
875 software or hardware security device.
876 leftckaid
878 The hex CKAID of the X.509 certificate. Certificates are stored in
879 the NSS database.
880 leftauth
882 How the security gateways will authenticate to the other side in
883 the case of asymmetric authentication; acceptable values are rsasig
884 or rsa for RSA Authentication with SHA-1, rsa-sha2 for RSA-PSS
885 digital signatures based authentication with SHA2-256, rsa-sha2_384
886 for RSA-PSS digital signatures based authentication with SHA2-384,
887 rsa-sha2_512 for RSA-PSS digital signatures based authentication
888 with SHA2-512, ecdsa for ECDSA digital signatures based
889 authentication, secret for shared secrets (PSK) authentication and
890 null for null-authentication. There is no default value - if unset,
891 the symmetrical authby= keyword is used to determine the
892 authentication policy of the connection.
893 Asymmetric authentication is only supported with IKEv2. If
895 symmetric authentication is required, use authby= instead of
896 leftauth and rightauth. If leftauth is set, rightauth must also be
897 set and authby= must not be set. Asymmetric authentication cannot
898 use secret (psk) on one side and null on the other side - use psk
899 on both ends instead.
900 When using EAPONLY authentication, which omits the regular IKEv2
902 AUTH payload, leftauth= (or rightauth=) should be set to eaponly.
903 Be aware that the symmetric keyword is authby= but the asymmetric
905 keyword is leftauth and rightauth (without the "by").
906 leftautheap
908 Whether the security gateways will authenticate uing an EAP method.
909 Acceptable values are none (the default) and tls for EAPTLS. If EAP
910 is the only authentication method, set leftauth=none in addition to
911 leftautheap=tls=.
912 The EAP authentication mechanisms are only available for IKEv2
914 based connections.
915 leftca
917 specifies the authorized Certificate Authority (CA) that signed the
918 certificate of the peer. If undefined, it defaults to the CA that
919 signed the certificate specified in leftcert. The special
920 rightca=%same is implied when not specifying a rightca and means
921 that only peers with certificates signed by the same CA as the
922 leftca will be allowed. This option is only useful in complex multi
923 CA certificate situations. When using a single CA, it can be safely
924 omitted for both left and right.
925 leftikeport
927 The UDP IKE port to listen on or send data to. This port cannot be
928 0 or 500. For TCP, see tcp-remoteport=
929 leftsendcert
931 This option configures when Libreswan will send X.509 certificates
932 to the remote host. Acceptable values are yes|always (signifying
933 that we should always send a certificate), sendifasked (signifying
934 that we should send a certificate if the remote end asks for it),
935 and no|never (signifying that we will never send a X.509
936 certificate). The default for this option is sendifasked which may
937 break compatibility with other vendor's IPsec implementations, such
938 as Cisco and SafeNet. If you find that you are getting errors about
939 no ID/Key found, you likely need to set this to always. This
940 per-conn option replaces the obsolete global nocrsend option.
941 leftxauthserver
943 Left is an XAUTH server. This can use PAM for authentication or md5
944 passwords in /etc/ipsec.d/passwd. These are additional credentials
945 to verify the user identity, and should not be confused with the
946 XAUTH group secret, which is just a regular PSK defined in
947 ipsec.secrets. The other side of the connection should be
948 configured as rightxauthclient. XAUTH connections cannot rekey, so
949 rekey=no should be specified in this conn. For further details on
950 how to compile and use XAUTH, see README.XAUTH. Acceptable values
951 are yes or no (the default).
952 leftxauthclient
954 Left is an XAUTH client. The xauth connection will have to be
955 started interactively and cannot be configured using auto=start.
956 Instead, it has to be started from the commandline using ipsec auto
957 --up connname. You will then be prompted for the username and
958 password. To setup an XAUTH connection non-interactively, which
959 defeats the whole purpose of XAUTH, but is regularly requested by
960 users, it is possible to use a whack command - ipsec whack --name
961 baduser --ipsecgroup-xauth --xauthname badusername --xauthpass
962 password --initiate The other side of the connection should be
963 configured as rightxauthserver. Acceptable values are yes or no
964 (the default).
965 leftusername
967 The username associated with this connection. The username can be
968 the IKEv2 XAUTH username, a GSSAPI username or IKEv2 CP username.
969 For the XAUTH username, the XAUTH password can be configured in the
970 ipsec.secrets file. This option was previously called
971 leftxauthusername.
972 leftmodecfgserver
974 Left is a Mode Config server. It can push network configuration to
975 the client. Acceptable values are yes or no (the default).
976 leftmodecfgclient
978 Left is a Mode Config client. It can receive network configuration
979 from the server. Acceptable values are yes or no (the default).
980 xauthby
982 When IKEv1 XAUTH support is available, set the method used by XAUTH
983 to authenticate the user with IKEv1. The currently supported values
984 are file (the default), pam or alwaysok. The password file is
985 located at /etc/ipsec.d/passwd, and follows a syntax similar to the
986 Apache htpasswd file, except an additional connection name argument
987 (and optional static IP address) are also present:
988 username:password:conname:ipaddress
990 For supported password hashing methods, see crypt(3). If pluto is
992 running in FIPS mode, some hash methods, such as MD5, might not be
993 available. Threads are used to launch an xauth authentication
994 helper for file as well as PAM methods.
995 The alwaysok should only be used if the XAUTH user authentication
997 is not really used, but is required for interoperability, as it
998 defeats the whole point of XAUTH which is to rely on a secret only
999 known by a human. See also pam-authorize=yes
1000 xauthfail
1002 When XAUTH support is available, set the failure method desired
1003 when authentication has failed. The currently supported values are
1004 hard (the default) and soft. A soft failure means the IPsec SA is
1005 allowed to be established, as if authentication had passed
1006 successfully, but the XAUTH_FAILED environment variable will be set
1007 to 1 for the updown script, which can then be used to redirect the
1008 user into a walled garden, for example a payment portal.
1009 pam-authorize
1011 IKEv1 supports PAM authorization via XAUTH using xauthby=pam. IKEv2
1012 does not support receiving a plaintext username and password.
1013 Libreswan does not yet support EAP authentication methods for IKE.
1014 The pam-authorize=yes option performs an authorization call via
1015 PAM, but only includes the remote ID (not username or password).
1016 This allows for backends to disallow an ID based on non-password
1017 situations, such as "user disabled" or "user over quota". See also
1018 xauthby=pam
1019 modecfgpull
1021 Pull the Mode Config network information from the server.
1022 Acceptable values are yes or no (the default).
1023 modecfgdns, modecfgdomains, modecfgbanner
1025 When configured as IKEv1 ModeCFG or IKEv2 server, specifying any of
1026 these options will cause those options and values to be sent to the
1027 connecting client. Libreswan as a client will use these received
1028 options to either update /etc/resolv.conf or the running unbound
1029 DNS server. When the connection is brought down, the previous DNS
1030 resolving state is restored.
1031 The modecfgdns option takes a comma or space separated list of IP
1033 addresses that can be used for DNS resolution. The modecfgdomains
1034 option takes a comma or space separated list of internal domain
1035 names that are reachable via the supplied modecfgdns DNS servers.
1036 The IKEv1 split tunnel directive will be sent automatically if the
1038 xauth server side has configured a network other than 0.0.0.0/0.
1039 For IKEv2, this is automated via narrowing.
1040 remote-peer-type
1042 Set the remote peer type. This can enable additional processing
1043 during the IKE negotiation. Acceptable values are cisco or ietf
1044 (the default). When set to cisco, support for Cisco IPsec gateway
1045 redirection and Cisco obtained DNS and domainname are enabled. This
1046 includes automatically updating (and restoring) /etc/resolv.conf.
1047 These options require that XAUTH is also enabled on this
1048 connection.
1049 nm-configured
1051 Mark this connection as controlled by Network Manager. Acceptable
1052 values are yes or no (the default). Currently, setting this to yes
1053 will cause libreswan to skip reconfiguring resolv.conf when used
1054 with XAUTH and ModeConfig.
1055 encapsulation
1057 In some cases, for example when ESP packets are filtered or when a
1058 broken IPsec peer does not properly recognise NAT, it can be useful
1059 to force RFC-3948 encapsulation. In other cases, where IKE is
1060 NAT'ed but ESP packets can or should flow without encapsulation, it
1061 can be useful to ignore the NAT-Traversal auto-detection.
1062 encapsulation=yes forces the NAT detection code to lie and tell the
1063 remote peer that RFC-3948 encapsulation (ESP in port 4500 packets)
1064 is required. encapsulation=no ignores the NAT detection causing
1065 ESP packets to send send without encapsulation. The default value
1066 of encapsulation=auto follows the regular outcome of the NAT
1067 auto-detection code performed in IKE. This option replaced the
1068 obsoleted forceencaps option.
1069 enable-tcp
1071 Normally, IKE negotiation and ESP encapsulation happens over UDP.
1072 This option enables support for IKE and ESP over TCP as per RFC
1073 8229. Acceptable values are no(the default), yes meaning only TCP
1074 will be used, or fallback meaning that TCP will be attempted only
1075 after negotiation over UDP failed. Since performance over TCP is
1076 much less, and TCP sessions are vulnerable to simply RST resets and
1077 MITM attacks causing the TCP connection to close, this option
1078 should really only be used in fallback mode. If used in fallback
1079 mode, it is recommend to reduce the retransmit-timeout from the
1080 default 60s to a much shorter value such as 10s, so that one does
1081 not have to wait a minute for the TCP fallback to be attempted.
1082 tcp-remoteport
1084 Which remote TCP port to use when IKE over TCP is attempted. The
1085 default value is to use the NAT-T IKE port (4500). This value is
1086 not negotiated and should be configured properly on all endpoints.
1087 When opening a TCP socket to the remote host in this port, a
1088 regular ephemeral source port is obtained from the OS. For changing
1089 the UDP ports, see leftikeport=
1090 nat-keepalive
1092 whether to send any NAT-T keep-alives. These one byte packets are
1093 send to prevent the NAT router from closing its port when there is
1094 not enough traffic on the IPsec connection. Acceptable values are:
1095 yes (the default) and no.
1096 initial-contact
1098 whether to send an INITIAL_CONTACT payload to the peer we are
1099 initiating to, if we currently have no IPsec SAs up with that peer.
1100 Acceptable values are: yes (the default) and no. It is recommended
1101 to leave this option set, unless multiple clients with the same
1102 identity are expected to connect using the same subnets and should
1103 operate at the same time. Or if a reconnecting client should not
1104 delete its old instance (eg perhaps it is still running). This is
1105 unlikely to be true.
1106 cisco-unity
1108 whether to send a CISCO_UNITY payload to the peer. Acceptable
1109 values are: no (the default) and yes. It is recommended to leave
1110 this option unset, unless the remote peer (Cisco client or server)
1111 requires it. This option does not modify local behaviour. It can be
1112 needed to connect as a client to a Cisco server. It can also be
1113 needed to act as a server for a Cisco client, which otherwise might
1114 send back an error DEL_REASON_NON_UNITY_PEER.
1115 ignore-peer-dns
1117 whether to ignore received DNS configuration. Acceptable values
1118 are: no (the default) and yes. Normally, when a roadwarrior
1119 connects to a remote VPN, the remote VPN server sends a list of DNS
1120 domains and DNS nameserver IP addresses that the roadwarrior can
1121 use to reach internal only resources through the VPN. This option
1122 allows the roadwarrior to ignore the server's suggestion. The
1123 roadwarrior will normally use this information to update the DNS
1124 resolving process. What is changed depends on the detected DNS
1125 configuration. It can modify /etc/resolv.conf directly, or
1126 reconfigure a locally running DNS server (unbound, knot, stubby or
1127 systemd-resolved) or inform NetworkManager.
1128 accept-redirect
1130 Whether requests of the remote peer to redirect IKE/IPsec SA's are
1131 accepted. Valid options are no (the default) and yes. See also
1132 accept-redirect-to.
1133 accept-redirect-to
1135 Specify the comma separated list of addresses we accept being
1136 redirected to. Both IPv4 and IPv6 addresses are supported as well
1137 the FQDNs. The value %any, as well as not specifying any address,
1138 signifes that we will redirect to any address gateway sends us in
1139 REDIRECT notify payload.
1140 The value of this option is not considered at all if
1142 accept-redirect is set to no.
1143 send-redirect
1145 Whether to send requests for the remote peer to redirect IKE/IPsec
1146 SA's during IKE_AUTH. Valid options are no (the default) and yes.
1147 If set, the option redirect-to= must also be set to indicate where
1148 to redirect peers to. For redirection during IKE_SA_INIT exchange,
1149 see the global-redirect= and global-redirect-to= options. Runtime
1150 redirects can be triggered via the ipsec whack --redirect command.
1151 redirect-to
1153 Where to send remote peers to via the send-redirect option. This
1154 can be an IP address or hostname (FQDN).
1155 fake-strongswan
1157 whether to send a STRONGSWAN Vendor ID payload to the peer.
1158 Acceptable values are: no (the default) and yes. This used to be
1159 required because strongswan rejects certain proposals with private
1160 use numbers such as esp=twofish or esp=serpent unless it receives a
1161 strongswan vendorid by the peer. This option sends such an
1162 (unversioned) vendor id. Note that libreswan and strongswan no
1163 longer support twofish or serpent, so enabling this option likely
1164 will no longer do anything.
1165 send-vendorid
1167 whether to send our Vendor ID during IKE. Acceptable values are: no
1168 (the default) and yes. The vendor id sent can be configured using
1169 the "config setup" option myvendorid=. It defaults to
1170 OE-Libreswan-VERSION.
1171 Vendor ID's can be useful in tracking interoperability problems.
1173 However, specific vendor identification and software versions can
1174 be useful to an attacker when there are known vulnerabilities to a
1175 specific vendor/version.
1176 The prefix OE stands for "Opportunistic Encryption". This prefix
1178 was historically used by The FreeS/WAN Project and The Openswan
1179 Project (openswan up to version 2.6.38) and in one Xeleranized
1180 openswan versions (2.6.39). Further Xeleranized openswan's use the
1181 prefix OSW.
1182 overlapip
1184 a boolean (yes/no) that determines, when (left|right)subnet=vhost:
1185 is used, if the virtual IP claimed by this states created from this
1186 connection can with states created from other connections.
1187 Note that connection instances created by the Opportunistic
1189 Encryption or PKIX (x.509) instantiation system are distinct
1190 internally. They will inherit this policy bit.
1191 The default is no.
1193 This feature is only available with kernel drivers that support SAs
1195 to overlapping conns. At present only the (klips) mast protocol
1196 stack supports this feature.
1197 reqid
1199 a unique identifier used to match IPsec SAs using iptables with
1200 XFRM. This identifier is normally automatically allocated in groups
1201 of 4. It is exported to the _updown script as REQID. On Linux,
1202 reqids are supported with IP Connection Tracking and NAT
1203 (iptables). Automatically generated values use the range 16380 and
1204 higher. Manually specified reqid values therefore must be between 1
1205 and 16379.
1206 Automatically generated reqids use a range of 0-3 (eg 16380-16383
1208 for the first reqid). These are used depending on the exact policy
1209 (AH, AH+ESP, IPCOMP, etc).
1210 WARNING: Manually assigned reqids are all identical. Instantiations
1212 of connections (those using %any wildcards) will all use the same
1213 reqid. If you use manual assigning you should make sure your
1214 connections only match single road warrior only or you break
1215 multiple road warriors behind same NAT router because this feature
1216 requires unique reqids to work.
1217 dpddelay
1219 Set the delay (in time units, defaults to seconds) between Dead
1220 Peer Detection (IKEv1 RFC 3706) or IKEv2 Liveness keepalives that
1221 are sent for this connection (default 0 seconds). Set to enable
1222 checking. If dpddelay is set, dpdtimeout also needs to be set.
1223 dpdtimeout
1225 Set the length of time (in time units, defaults to seconds) that we
1226 will idle without hearing back from our peer. After this period has
1227 elapsed with no response and no traffic, we will declare the peer
1228 dead, and remove the SA (default 0 seconds). Set value bigger than
1229 dpddelay to enable. If dpdtimeout is set, dpddelay also needs to be
1230 set.
1231 dpdaction
1233 When a DPD enabled peer is declared dead, what action should be
1234 taken. hold (default) means the eroute will be put into %hold
1235 status, while clear means the eroute and SA with both be cleared.
1236 restart means that ALL SAs to the dead peer will renegotiated.
1237 dpdaction=clear is really only useful on the server of a Road
1239 Warrior config.
1240 The value restart_by_peer has been obsoleted and its functionality
1242 moved into the regular restart action.
1243 pfs
1245 whether Perfect Forward Secrecy of keys is desired on the
1246 connection's keying channel (with PFS, penetration of the
1247 key-exchange protocol does not compromise keys negotiated earlier);
1248 Acceptable values are yes (the default) and no.
1249 pfsgroup
1251 This option is obsoleted, please use phase2alg if you need the PFS
1252 to be different from phase1 (the default) using:
1253 phase2alg=aes128-md5;modp1024
1254 aggressive
1256 Use IKEv1 Aggressive Mode instead of IKEv1 Main Mode. This option
1257 has no effect when IKEv2 is used. Acceptable values are no (the
1258 default) or yes. When this option is enabled, IKEv1 Main Mode will
1259 no longer be allowed for this connection. The old name of this
1260 option was aggrmode.
1261 Aggressive Mode is less secure, and more vulnerable to Denial Of
1263 Service attacks. It is also vulnerable to brute force attacks with
1264 software such as ikecrack. It should not be used, and it should
1265 especially not be used with XAUTH and group secrets (PSK). If the
1266 remote system administrator insists on staying irresponsible,
1267 enable this option.
1268 Aggressive Mode is further limited to only proposals with one DH
1270 group as there is no room to negotiate the DH group. Therefore it
1271 is mandatory for Aggressive Mode connections that both ike= and
1272 phase2alg= options are specified with only one fully specified
1273 proposal using one DH group.
1274 The KE payload is created in the first exchange packet when using
1276 aggressive mode. The KE payload depends on the DH group used. This
1277 is why there cannot be multiple DH groups in IKEv1 aggressive mode.
1278 In IKEv2, which uses a similar method to IKEv1 Aggressive Mode,
1279 there is an INVALID_KE response payload that can inform the
1280 initiator of the responder's desired DH group and so an IKEv2
1281 connection can actually recover from picking the wrong DH group by
1282 restarting its negotiation.
1283 salifetime
1285 how long a particular instance of a connection (a set of
1286 encryption/authentication keys for user packets) should last, from
1287 successful negotiation to expiry; acceptable values are an integer
1288 optionally followed by s (a time in seconds) or a decimal number
1289 followed by m, h, or d (a time in minutes, hours, or days
1290 respectively) (default 8h, maximum 24h). Normally, the connection
1291 is renegotiated (via the keying channel) before it expires. The two
1292 ends need not exactly agree on salifetime, although if they do not,
1293 there will be some clutter of superseded connections on the end
1294 which thinks the lifetime is longer.
1295 The keywords "keylife" and "lifetime" are obsoleted aliases for
1297 "salifetime." Change your configs to use "salifetime" instead.
1298 ipsec-max-bytes
1300 how many bytes can be sent, or how many bytes can be received on an
1301 IPsec SA instance for a connection; acceptable values are an
1302 integer optionally followed by KiB, MiB, GiB, TiB, PiB or EiB to
1303 signify kilobytes, megabytes, gigabytes, terabytes, petabytes or
1304 exabytes.
1305 An IPsec SA contains two keys, one for inbound and one for outbound
1307 traffic. The ipsec-max-bytes sets two limits on each of these keys:
1308 the hard limit which is the total number of bytes that a given key
1309 can encrypt, and the soft limit which is the number of bytes that
1310 can be encrypted before a renegotiation of the IPsec SA is
1311 initiated. Normally the renegotation (via the IKE SA) is completed
1312 before the ipsec-max-bytes value is reached.
1313 Pluto sets the the original initiator's soft limit to 25% of
1315 ipsec-max-bytes (with 12% fuzz) and on the original responder's
1316 soft limit to 50% of ipsec-max-bytes (with 12% fuzz). This way the
1317 original initiator hopefully is the one initiating the
1318 renegotiation of the IPsec SA.
1319 This option is not negotiated between IKE peers. Each end of the
1321 IPsec SA sets their own limits independently.
1322 The default (hard limit) is 2^63 bytes. The original initiator's
1324 soft limit is 2^61 bytes (approx.) and the original responder's
1325 soft limit is 2^62 bytes (approx.).
1326 ipsec-max-packets
1328 how many packets can be sent/received on a particular instance of a
1329 connection (a set of encryption/authentication keys for user
1330 packets) , from successful negotiation to expiry.
1331 Default values and caveats are the same as for ipsec-max-bytes.
1333 This option uses a prefix without "B" for bytes.
1334 replay-window
1336 The size of the IPsec SA replay window protection in packets.
1337 Kernels (Linux, and most BSDs) support a window size of at least
1338 2040 packets. The default replay window size is 128 packets.
1339 A value of 0 disables replay protection. Disabling of replay
1341 protection is sometimes used on a pair of IPsec servers in a High
1342 Availability setup, or on servers with very unpredictable latency,
1343 such as mobile networks, which can cause an excessive amount of out
1344 of order packets.
1345 Disabling replay protection will also disable Extended Sequence
1347 Numbers (esn=no), as advise from RFC 4303 caused some stacks to not
1348 support ESN without a replay-window.
1349 Note: on Linux, sequence errors can be seen in /proc/net/xfrm_stat.
1351 Note: the BSD setkey utility displays the replay window size in
1353 bytes (8 packets per byte) and not packets.
1354 Technically, at least the Linux kernel can install IPsec SA's with
1356 an IPsec SA Sequence Number, but this is currently not supported by
1357 libreswan.
1358 rekey
1360 whether a connection should be renegotiated when it is about to
1361 expire; acceptable values are yes (the default) and no. The two
1362 ends need not agree, but while a value of no prevents Pluto from
1363 requesting renegotiation, it does not prevent responding to
1364 renegotiation requested from the other end, so no will be largely
1365 ineffective unless both ends agree on it.
1366 rekeymargin
1368 how long before connection expiry or keying-channel expiry should
1369 attempts to negotiate a replacement begin; acceptable values as for
1370 salifetime (default 9m). Relevant only locally, other end need not
1371 agree on it.
1372 rekeyfuzz
1374 maximum percentage by which rekeymargin should be randomly
1375 increased to randomize rekeying intervals (important for hosts with
1376 many connections); acceptable values are an integer, which may
1377 exceed 100, followed by a `%' (default set by ipsec_pluto(8),
1378 currently 100%). The value of rekeymargin, after this random
1379 increase, must not exceed salifetime. The value 0% will suppress
1380 time randomization. Relevant only locally, other end need not agree
1381 on it.
1382 keyingtries
1384 how many attempts (a whole number or %forever) should be made to
1385 negotiate a connection, or a replacement for one, before giving up
1386 (default %forever). The value %forever or 0 means to keep trying
1387 forever. For Opportunistic Encryption connections, a keyingtries
1388 value of %forever or 0 is set to 1 and a warning message will be
1389 logged. This is because an expired failureshunt triggers new
1390 keyingtries on-demand later, when there is traffic. This prevents
1391 accumulating an infinite amount of attempts to peers that do not
1392 support Opportunistic Encryption. For Opportunistic, a keyingtries
1393 value of > 1 is allowed but currently not recommended. The meaning
1394 of failureshunt= is unclear when there is continued (failed) keying
1395 happening with a negotiationshunt installed. Relevant only locally,
1396 other end need not agree on it.
1397 ikelifetime
1399 how long the keying channel of a connection (buzzphrase: “IKE SA”
1400 or “Parent SA”) should last before being renegotiated; acceptable
1401 values as for salifetime. The default as of version 4.2 is 8h,
1402 before that it was 1h. The maximum is 24h. The two-ends-disagree
1403 case is similar to that of salifetime.
1404 retransmit-timeout
1406 how long a single packet, including retransmits of that packet, may
1407 take before the IKE attempt is aborted. If rekeying is enabled, a
1408 new IKE attempt is started. The default set by ipsec_pluto(8),
1409 currently is 60s. See also: retransmit-interval, rekey and
1410 keyingtries.
1411 retransmit-interval
1413 the initial interval time period, specified in msecs, that pluto
1414 waits before retransmitting an IKE packet. This interval is doubled
1415 for each attempt (exponential back-off). The default set by
1416 ipsec_pluto(8), currently is 500. See also: retransmit-timeout,
1417 rekey and keyingtries.
1418 compress
1420 whether IPComp compression of content is proposed on the connection
1421 (link-level compression does not work on encrypted data, so to be
1422 effective, compression must be done before encryption); acceptable
1423 values are yes and no (the default).
1424 For IKEv1, compress settings on both peers must match. For IKEv2,
1426 compression can only be suggested and a mismatched compress setting
1427 results in connection without compression.
1428 When set to yes, compression is negotiated for the DEFLATE
1430 compression algorithm.
1431 metric
1433 Set the metric for added routes. This value is passed to the
1434 _updown scripts as PLUTO_METRIC. Acceptable values are positive
1435 numbers, with the default being 1.
1436 mtu
1438 Set the MTU for the route(s) to the remote endpoint and/or subnets.
1439 This is sometimes required when the overhead of the IPsec
1440 encapsulation would cause the packet the become too big for a
1441 router on the path. Since IPsec cannot trust any unauthenticated
1442 ICMP messages, PATH MTU discovery does not work. This can also be
1443 needed when using "6to4" IPV6 deployments, which adds another
1444 header on the packet size. Acceptable values are positive numbers.
1445 There is no default.
1446 tfc
1448 Enable Traffic Flow Confidentiality ("TFC") (RFC-4303) for outgoing
1449 ESP packets in Tunnel Mode. When enabled, ESP packets are padded to
1450 the specified size (up to the PMTU size) to prevent leaking
1451 information based on ESP packet size. This option is ignored for AH
1452 and for ESP in Transport Mode as those always leak traffic
1453 characteristics and applying TFC will not do anything. Acceptable
1454 values are positive numbers. The value 0 means TFC padding is not
1455 performed. Currently this feature is only implemented for the Linux
1456 XFRM stack. In IKEv2, when the notify payload
1457 ESP_TFC_PADDING_NOT_SUPPORTED is received, TFC padding is disabled.
1458 The default is not to do any TFC padding, but this might change in
1459 the near future.
1460 send-no-esp-tfc
1462 Whether or not to tell the remote peer that we do not support
1463 Traffic Flow Confidentiality ("TFC") (RFC-4303). Possible values
1464 are no (the default) which allows the peer to use TFC or yes which
1465 prevents to peer from using TFC. This does not affect whether this
1466 endpoint uses TFC, which only depends on the local tfc setting.
1467 This option is only valid for IKEv2.
1468 nflog
1470 If set, the NFLOG group number to log this connection's pre-crypt
1471 and post-decrypt traffic to. The default value of 0 means no
1472 logging at all. This option is only available on linux kernel
1473 2.6.14 and later. It allows common network utilities such as
1474 tcpdump, wireshark and dumpcap, to use nflog:XXX pseudo interfaces
1475 where XXX is the nflog group number. During the updown phase of a
1476 connection, iptables will be used to add and remove the
1477 source/destination pair to the nflog group specified. The rules are
1478 setup with the nflog-prefix matching the connection name. See also
1479 the global nflog-all option.
1480 mark
1482 If set, the MARK to set for the IPsec SA of this connection. The
1483 format of a CONNMARK is mark/mask. If the mask is left out, a
1484 default mask of 0xffffffff is used. A mark value of -1 means to
1485 assign a new global unique mark number for each instance of the
1486 connection. Global marks start at 1001. This option is only
1487 available on linux XFRM kernels. It can be used with iptables to
1488 create custom iptables rules using CONNMARK. It can also be used
1489 with Virtual Tunnel Interfaces ("VTI") to direct marked traffic to
1490 specific vtiXX devices.
1491 mark-in
1493 The same as mark, but mark-in only applies to the inbound half of
1494 the IPsec SA. It overrides any mark= setting.
1495 mark-out
1497 The same as mark, but mark-out only applies to the outbound half of
1498 the IPsec SA. It overrides any mark= setting.
1499 vti-interface
1501 This option is used to create "Routing based VPNs" (as opposed to
1502 "Policy based VPNs"). It will create a new interface that can be
1503 used to route traffic in for encryption/decryption. The Virtual
1504 Tunnel Interface ("VTI") interface name is used to for all IPsec
1505 SA's created by this connection. This requires that the connection
1506 also enables either the mark= or mark-in= / mark-out- option(s).
1507 All traffic marked with the proper MARKs will be automatically
1508 encrypted if there is an IPsec SA policy covering the
1509 source/destination traffic. Tools such as tcpdump and iptables can
1510 be used on all cleartext pre-encrypt and post-decrypt traffic on
1511 the device. See the libreswan wiki for example configurations that
1512 use VTI.
1513 VTI interfaces are currently only supported on Linux with XFRM. The
1515 _updown script handles certain Linux specific interfaces settings
1516 required for proper functioning (disable_policy, rp_filter,
1517 forwarding, etc). Interface names are limited to 16 characters and
1518 may not allow all characters to be used. If marking and
1519 vti-routing=yes is used, no manual iptables should be required.
1520 However, administrators can use the iptables mangle table to mark
1521 traffic manually if desired.
1522 vti-routing
1524 Whether or not to add network rules or routes for IPsec SA's to the
1525 respective VTI devices. Valid values are yes (the default) or no.
1526 When using "routing based VPNs" with a subnets policy of 0.0.0.0/0,
1527 this setting needs to set to no to prevent imploding the tunnel,
1528 and the administrator is expected to manually add ip rules and ip
1529 routes to configure what traffic must be encrypted. When set to
1530 yes, the _updown script will automatically route the
1531 leftsubnet/rightsubnet traffic into the VTI device specified with
1532 vti-interface
1533 vti-shared
1535 Whether or not the VTI device is shared amongst connections. Valid
1536 values are no (the default) or yes. When set to no, the VTI device
1537 is automatically deleted if the connection is a single
1538 non-instantiated connection. If a connection instantiates (eg
1539 right=%any) then this option has no effect, as the VTI device is
1540 not removed as it is shared with multiple roadwarriors.
1541 ipsec-interface
1543 Create or use an existing virtual interface ipsecXXX for "Routing
1544 based VPNs" (as opposed to "Policy based VPNs"). Valid options are
1545 yes, no or a number. When using a number, the IPsec interface
1546 created and/or used will use that number as part of the interface
1547 name. For example setting ipsec-interface=5 will create and/or use
1548 the ipsec5 interface. The value 0 cannot be used and is interpreted
1549 as no. The value yes is interpreted as the number 1, and thus will
1550 use the interface named ipsec1. An IP address can be configured for
1551 this interface via the interface-ip= option.
1552 The ipsec-interface is used to route outbound traffic that needs to
1554 be encrypted, and will decrypt inbound traffic that arrives on this
1555 interface. All traffic that is routed to this interface will be
1556 automatically encrypted providing the IPsec SA policy covers this
1557 traffic. Traffic not matching the IPsec SA will be dropped. Tools
1558 such as tcpdump, iptables, ifconfig and tools that need traffic
1559 counters can be used on all cleartext pre-encrypt and post-decrypt
1560 traffic on the device. When leftsubnet= is equal to rightsubnet=,
1561 the routing needs to be manged by an external routing daemon or
1562 manually by the administrator.
1563 This option is currently only supported on Linux kernels 4.19 or
1565 later when compiled with XFRMi support (CONFIG_XFRM_INTERFACE). The
1566 number of the ipsecX device corresponds with the XFRM IF_ID policy
1567 option of the IPsec SA in the Linux kernel. On Linux, XFRMi
1568 interfaces can be managed by libreswan automatically or can be
1569 preconfigured on the system using the existing init system or via
1570 networking tools such as systemd-networkd and NetworkManager. The
1571 _updown script handles certain Linux specific interfaces settings
1572 required for proper functioning, such as forwarding and routing
1573 rules for IPsec traffic.
1574 The ipsec-interface=0 will create an interface with the same name
1576 as the old KLIPS interface, ipsec0. This interface name should only
1577 be used when required for migration from KLIPS to XFRM interfaces.
1578 Since XFRM IF_ID and marking cannot use 0, this is mapped to 16384.
1579 This means that the devices ipsec0 and ipsec16384 cannot both be in
1580 use.
1581 interface-ip=
1583 NOTE: This option is currently not implemented pending pluto IP
1584 address reference counting. The IP address and netmask to configure
1585 on a virtual device (eg ipsecXXX). This is often used when building
1586 Routing based IPsec tunnels using transport mode and GRE, but can
1587 also be useful in other scenarios. Currently requires
1588 ipsec-interface=. See also leftvti= for cnofiguring IP addresses
1589 when using VTI.
1590 priority
1592 The priority in the kernel SPD/SAD database, when matching up
1593 packets. Each kernel (XFRM, OSX, etc) has its own mechanism for
1594 setting the priority. Setting this option to non-zero passes the
1595 priority to the kernel stack unmodified. The maximum value depends
1596 on the stack. It is recommended not to exceed 65536
1597 XFRM use a priority system based on "most specific match first". It
1599 uses an internal algorithm to calculate these based on network
1600 prefix length, protocol and port selectors. A lower value means a
1601 higher priority.
1602 Typical values are about the 2000 range. These can be seen on the
1604 XFRM stack using ip xfrm policy when the connection is up. For
1605 "anonymous IPsec" or Opportunistic Encryption based connections, a
1606 much lower priority (65535) is used to ensure administrator
1607 configured IPsec always takes precedence over opportunistic IPsec.
1608 sendca
1610 How much of our available X.509 trust chain to send with the End
1611 certificate, excluding any root CA's. Specifying issuer sends just
1612 the issuing intermediate CA, while
1613 all will send the entire chain of intermediate CA's.none (the
1614 default) will not send any CA certs.
1615 labeled-ipsec
1617 This option is obsolete. To enable labeled IPsec, setting the
1618 policy-label= is enough. See also policy-label= and
1619 secctx-attr-type=
1620 policy-label
1622 The string representation of an access control security label that
1623 is interpreted by the LSM (e.g. SELinux) for use with Labeled
1624 IPsec. See also labeled-ipsec= and secctx-attr-type=. For example,
1625 policy-label=system_u:object_r:ipsec_spd_t:s0-s15:c0.c1023
1626 failureshunt
1628 what to do with packets when negotiation fails. The default is
1629 none: no shunt; passthrough, drop, and reject have the obvious
1630 meanings.
1631 negotiationshunt
1633 What to do with packets during the IKE negotiation. Valid options
1634 are hold (the default) or passthrough. This should almost always be
1635 left to the default hold value to avoid cleartext packet leaking.
1636 The only reason to set this to passthrough is if plaintext service
1637 availability is more important than service security or privacy, a
1638 scenario that also implies failureshunt=passthrough and most likely
1639 authby=%null using Opportunistic Encryption.
1640
1642 At present, the only config section known to the IPsec software is the
1643 one named setup, which contains information used when the software is
1644 being started (see ipsec_setup(8)). Here's an example:
1645 config setup
1648 logfile=/var/log/pluto.log
1649 plutodebug=all
1650 Parameters are optional unless marked “(required)”.
1652 The currently-accepted parameter names in a config setup section are:
1654 protostack
1656 decide which protocol stack is going to be used. Valid values are
1657 "xfrm" and "bsd". This option should no longer be set, as the stack
1658 is currently auto-detected. The values "klips, "mast", "netkey",
1659 "native", "kame" and "auto" are obsolete. The option is kept only
1660 because it is suspected that Linux and BSD will get userspace
1661 stacks with IPsec support soon (such as dpdk).
1662 listen
1664 IP address to listen on, defaults to ANY. Currently only accepts
1665 one IP address.
1666 ike-socket-bufsize
1668 Set the IKE socket buffer size. Default size is determined by the
1669 OS (as of writing, this seems to be set to 212992. On Linux this is
1670 visible via /proc/sys/net/core/rmem_default and
1671 /proc/sys/net/core/wmem_default. On Linux, this option uses
1672 SO_RCVBUFFORCE and SO_SNDBUFFORCE so that it can override
1673 rmem_max/wmem_max values of the OS. This requires CAP_NET_ADMIN
1674 (which is also required for other tasks). This option can also be
1675 toggled on a running system using ipsec whack --ike-socket-bufsize
1676 bufsize.
1677 ike-socket-errqueue
1679 Whether to enable or disable receiving socket errors via
1680 IP_RECVERR. The default is enabled. This will cause the socket to
1681 receive, process and log socket errors, such as ICMP unreachable
1682 messages or Connection Refused messages. Disabling this only makes
1683 sense on very busy servers, and even then it might not make much of
1684 a difference. This option can also be toggled on a running system
1685 using ipsec whack --ike-socket-errqueue-toggle.
1686 listen-udp
1688 Whether the pluto IKE daemon should listen on the standard UDP
1689 ports of 500 and 4500. The value "yes" means to listen on these
1690 ports, and is the default. This should almost never be disabled. In
1691 the rare case where it is known that only ever TCP or non-standard
1692 UDP ports will be used, this option can disable the standard UDP
1693 ports. Connections can specify their own non-standard port using
1694 leftikeport=.
1695 listen-tcp
1697 Whether the pluto IKE daemon should listen on the (pseudo) standard
1698 TCP port 4500. The value "no" is the current default, but this will
1699 be changed in the future to "yes". The TCP usage complies to RFC
1700 8229 for IKE and ESP over TCP support. Connections can specify
1701 their own non-standard port using leftikeport=.
1702 nflog-all
1704 If set, the NFLOG group number to log all pre-crypt and
1705 post-decrypt traffic to. The default value of 0 means no logging at
1706 all. This option is only available on linux kernel 2.6.14 and
1707 later. It allows common network utilities such as tcpdump,
1708 wireshark and dumpcap, to use nflog:XXX pseudo interfaces where XXX
1709 is the nflog group number. During startup and shutdown of the IPsec
1710 service, iptables commands will be used to add or remove the global
1711 NFLOG table rules. The rules are setup with the nflog-prefix
1712 all-ipsec. See also the per-connection nflog option.
1713 keep-alive
1715 The delay (in seconds) for NAT-T keep-alive packets, if these are
1716 enabled using nat-keepalive This parameter may eventually become
1717 per-connection.
1718 virtual-private
1720 contains the networks that are allowed as (left|right)subnet= for
1721 the remote clients when using the vhost: or vnet: keywords in the
1722 (left|right)subnet= parameters. In other words, the address ranges
1723 that may live behind a NAT router through which a client connects.
1724 This value is usually set to all the RFC-1918 address space,
1725 excluding the space used in the local subnet behind the NAT (An IP
1726 address cannot live at two places at once). IPv4 address ranges are
1727 denoted as %v4:a.b.c.d/mm and IPv6 is denoted as
1728 %v6:aaaa::bbbb:cccc:dddd:eeee/mm. One can exclude subnets by using
1729 the !. For example, if the VPN server is giving access to
1730 192.168.1.0/24, this option should be set to:
1731 virtual-private=%v4:10.0.0.0/8,%v4:192.168.0.0/16,%v4:172.16.0.0/12,%v4:!192.168.1.0/24.
1732 This parameter is only needed on the server side and not on the
1733 client side that resides behind the NAT router, as the client will
1734 just use its IP address for the inner IP setting. This parameter
1735 may eventually become per-connection. See also leftsubnet=
1736 Note: It seems that T-Mobile in the US and Rogers/Fido in Canada
1738 have started using 25.0.0.0/8 as their pre-NAT range. This range
1739 technically belongs to the Defence Interoperable Network Services
1740 Authority (DINSA), an agency of the Ministry of Defence of the
1741 United Kingdom. The network range seems to not have been announced
1742 for decades, which is probably why these organisations "borrowed"
1743 this range. To support roadwarriors on these 3G networks, you might
1744 have to add it to the virtual-private= line.
1745 myvendorid
1747 The string to use as our vendor id (VID) when send-vendorid=yes.
1748 The default is OE-Libreswan-VERSION.
1749 nhelpers
1751 how many pluto helpers are started to help with cryptographic
1752 operations. Pluto will start as many helpers as the number of
1753 CPU's, minus 1 to dedicate to the main thread. For machines with
1754 less than 4 CPU's, an equal number of helpers to CPU's are started.
1755 A value of 0 forces pluto to do all operations inline using the
1756 main process. A value of -1 tells pluto to perform the above
1757 calculation. Any other value forces the number to that amount.
1758 seedbits
1760 Pluto uses the NSS crypto library as its random source. Some
1761 government Three Letter Agencies require that pluto reads
1762 additional bits from /dev/random and feed these into the NSS RNG
1763 before drawing random from the NSS library, despite the NSS library
1764 itself already seeding its internal state. This process can block
1765 pluto for an extended time during startup, depending on the entropy
1766 of the system. Therefore, the default is to not perform this
1767 redundant seeding. If specifying a value, it is recommended to
1768 specify at least 460 bits (for FIPS) or 440 bits (for BSI).
1769 ikev1-secctx-attr-type
1771 The value for the IKEv1 IPsec SA security context attribute
1772 identifier that is used for Labeled IPsec. Defaults to the private
1773 use IANA value 32001 from the IPsec SA attributes registry. Old
1774 openswan versions might still be using the (stolen) value 10, which
1775 has since been assigned by IANA for something else. Other values
1776 are not recommended unless IANA assigns an actual value for this
1777 option. Labeled IPsec using IKEv2 does not use this option, it only
1778 uses an IANA allocated Notify number. See also policy-label.
1779 ikev1-policy
1781 What to do with received IKEv1 packets. Valid options are accept
1782 (default), reject which will reply with an error, and drop which
1783 will silently drop any received IKEv1 packet. If this option is set
1784 to drop or reject, an attempt to load an IKEv1 connection will
1785 fail, as these connections would never be able to receive a packet
1786 for processing.
1787 crlcheckinterval
1789 interval expressed in second units, for example crlcheckinterval=8h
1790 for 8 hours, after which pluto will fetch new Certificate
1791 Revocation List (CRL) from crl distribution points. List of used
1792 CRL distribution points are collected from CA certificates and end
1793 certificates. Loaded X.509 CRL's are verified to be valid and
1794 updates are imported to NSS database. If set to 0, which is also
1795 the default value if this option is not specified, CRL updating is
1796 disabled.
1797 crl-strict
1799 if not set, pluto is tolerant about missing or expired X.509
1800 Certificate Revocation Lists (CRL's), and will allow peer
1801 certificates as long as they do not appear on an expired CRL. When
1802 this option is enabled, all connections with an expired or missing
1803 CRL will be denied. Active connections will be terminated at rekey
1804 time. This setup is more secure, but vulnerable to downtime if the
1805 CRL expires. Acceptable values are yes or no (the default). This
1806 option used to be called strictcrlpolicy.
1807 curl-iface
1809 The name of the interface that is used for CURL lookups. This is
1810 needed on rare situations where the interface needs to be forced to
1811 be different from the default interface used based on the routing
1812 table.
1813 curl-timeout
1815 The timeout for the curl library calls used to fetch CRL and OCSP
1816 requests. The default is 5s.
1817 ocsp-enable
1819 Whether to perform Online Certificate Store Protocol ("OCSP")
1820 checks on those certificates that have an OCSP URI defined.
1821 Acceptable values are yes or no (the default).
1822 ocsp-strict
1824 if set to no, pluto is tolerant about failing to obtain an OCSP
1825 responses and a certificate is not rejected when the OCSP request
1826 fails, only when the OCSP request succeeds and lists the
1827 certificate as revoked. If set to yes, any failure on obtaining an
1828 OCSP status for a certificate will be fatal and the certificate
1829 will be rejected. Acceptable values are yes or no (the default).
1830 The strict mode refers to the NSS
1832 ocspMode_FailureIsVerificationFailure mode, while non-strict mode
1833 refers to the NSS ocspMode_FailureIsNotAVerificationFailure mode.
1834 ocsp-method
1836 The HTTP methods used for fetching OCSP data. Valid options are get
1837 (the default) and post. Note that this behaviour depends on the NSS
1838 crypto library that is actually performing the fetching. When set
1839 to the get method, post is attempted only as fallback in case of
1840 failure. When set to post, only the post method is ever used.
1841 ocsp-timeout
1843 The time until an OCSP request is aborted and considered failed.
1844 The default value is 2 seconds.
1845 ocsp-uri
1847 The URI to use for OCSP requests instead of the default OCSP URI
1848 listed in the CA certificate. This requires the ocsp-trustname
1849 option to be set to the nick (friendly name) of the OCSP server
1850 certificate, which needs to be present in the NSS database. These
1851 option combined with the next option sets the OCSP default
1852 responder.
1853 ocsp-trustname
1855 The nickname of the certificate that has been imported into the NSS
1856 database of the server handling the OCSP requests. This requires
1857 the ocsp-uri option to be set as well. This option and the previous
1858 options sets the OCSP default responder.
1859 ocsp-cache-size
1861 The maximum size (in number of certificates) of OCSP responses that
1862 will be kept in the cache. The default is 1000. Setting this value
1863 to 0 means the cache is disabled.
1864 ocsp-cache-min-age
1866 The minimum age (in seconds) before a new fetch will be attempted.
1867 The default is 1 hour.
1868 ocsp-cache-max-age
1870 The maximum age (in seconds) before a new fetch will be attempted.
1871 The default is 1 day.
1872 syslog
1874 the syslog(2) “facility” name and priority to use for
1875 startup/shutdown log messages, default daemon.error.
1876 plutodebug
1878 how much Pluto debugging output should be logged. An empty value,
1879 or the magic value none, means no debug output (the default).
1880 Otherwise only the specified types of output (a quoted list, names
1881 without the --debug- prefix, separated by white space) are enabled;
1882 The current option values are base that represents moderate amounts
1884 of information, cpu-usage for getting timing/load based information
1885 (best used without any other debugging options), crypt for all
1886 crypto related operations and tmi (Too Much Information) for
1887 excessive logging. To log any sensitive private key or password
1888 material, use the special private value.
1889 The old plutodebug options (control, controlmore, x509, kernel,
1891 etc) are mapped to either base or tmi. Note that all maps to base
1892 and not tmi.
1893 uniqueids
1895 Whether IDs should be considered identifying remote parties
1896 uniquely. Acceptable values are yes (the default) and no.
1897 Participant IDs normally are unique, so a new connection instance
1898 using the same remote ID is almost invariably intended to replace
1899 an old existing connection.
1900 When the connection is defined to be a server (using xauthserver=)
1902 and the connection policy is authby=secret, this option is ignored
1903 (as of 3.20) and old connections will never be replaced. This
1904 situation is commonly known as clients using a "Group ID".
1905 This option may disappear in the near future. People using
1907 identical X.509 certificates on multiple devices are urged to
1908 upgrade to use separate certificates per client and device.
1909 logfile
1911 do not use syslog, but rather log to stderr, and direct stderr to
1912 the argument file. This option used to be called plutostderrlog=
1913 logappend
1915 If pluto is instructed to log to a file using logfile=, this option
1916 determines whether the log file should be appended to or
1917 overwritten. Valid options are yes (the default) to append and no
1918 to overwrite. Since on modern systems, pluto is restarted by other
1919 daemons, such as systemd, this option should be left at its default
1920 yes value to preserve the log entries of previous runs of pluto.
1921 The option is mainly of use for running the test suite, which needs
1922 to create new log files from scratch.
1923 logip
1925 If pluto is instructed to log the IP address of incoming
1926 connections. Valid options are yes (the default) and no. Note that
1927 this only affects regular logging. Any enabled debugging via
1928 plutodebug= will still contain IP addresses of peers. This option
1929 is mostly meant for servers that want to avoid logging IP addresses
1930 of incoming clients. Other identifiable information might still be
1931 logged, such as ID payloads and X.509 certificate details. When
1932 using ID of type IP address, this option will not hide the actual
1933 IP address as part of the ID. Most deployments will not want to
1934 change this from the default. If logging of IP addresses is
1935 unwanted, audit-log=no should also be set.
1936 audit-log
1938 Whether pluto should produce Linux Auditing System log messages. If
1939 enabled, pluto will log start, stop and fail for the negotiation of
1940 IKE and IPsec SA's. The kernel will also log success and failures
1941 for actually adding and removing IPsec SA's from the kernel's SADB.
1942 Valid options are yes(the default) and no. On non-Linux systems,
1943 this option is ignored. If enabled but the kernel is lacking audit
1944 support, audit messages are not sent. If the kernel has audit
1945 support and using it fails, pluto will abort. Note that for
1946 compliance reasons, audit log messages contain the relevant IP
1947 addresses, even if logip=no.
1948 logtime
1950 When pluto is directed to log to a file using logfile=, this option
1951 determines whether or not to log the current timestamp as prefix.
1952 Values are yes (the default) or no. The no value can be used to
1953 create logs without ephemeral timestamps, such as those created
1954 when running the test suite. This option used to be called
1955 plutostderrlogtime=
1956 ddos-mode
1958 The startup mode of the DDoS defense mechanism. Acceptable values
1959 are busy, unlimited or auto (the default). This option can also be
1960 given to the IKE daemon while running, for example by issuing ipsec
1961 whack --ddos--busy. When in busy mode, pluto activates anti-DDoS
1962 counter measures. Currently, counter measures consist of requiring
1963 IKEv2 anti-DDoS cookies on new incoming IKE requests, and a more
1964 aggressive cleanup of partially established or AUTH_NULL
1965 connections.
1966 ddos-ike-threshold
1968 The number of half-open IKE SAs before the pluto IKE daemon will be
1969 placed in busy mode. When in busy mode, pluto activates anti-DDoS
1970 counter measures. The default is 25000. See also ddos-mode and
1971 ipsec whack --ddos-XXX.
1972 global-redirect
1974 Whether to send requests for the remote peer to redirect IKE/IPsec
1975 SA's during IKE_SA_INIT. Valid options are no (the default), yes
1976 and auto, where auto means that the requests will be sent if DDoS
1977 mode is active (see ddos-mode). If set, the option
1978 global-redirect-to= must also be set to indicate where to redirect
1979 peers to. For specific connection redirection after IKE SA
1980 authentication, see the send-redirect= and redirect-to= options.
1981 This configuration can be changed at runtime via the ipsec whack
1982 --global-redirect command.
1983 global-redirect-to
1985 Where to send remote peers to via the global-redirect option. This
1986 can be a list, or a single entry, of IP addresses or hostnames
1987 (FQDNs). If there is a list of entries, they must be separated with
1988 comma's. One specified entry means all peers will be redirected to
1989 it, while multiple specified entries means peers will be evenly
1990 distributed across the specified servers. This configuration can be
1991 changed at runtime via the ipsec whack --global-redirect-to
1992 command.
1993 max-halfopen-ike
1995 The number of half-open IKE SAs before the IKE daemon starts
1996 refusing all new IKE attempts. Established IKE peers are not
1997 affected. The default value is 50000.
1998 shuntlifetime
2000 The time until bare shunts (kernel policies not associated with
2001 connections) are deleted from the kernel. The default value is 15m.
2002 When using Opportunistic Encryption to a specific host fails, the
2003 system will either install a %pass or %hold shunt to let the
2004 traffic out clear text or block it. During the the shuntlifetime,
2005 no new Opportunistic Encryption attempt will be started, although
2006 the system will still respond to incoming OE requests from the
2007 remote IP. See also failureshunt and negotiationshunt
2008 xfrmlifetime
2010 The time in seconds until the XFRM acquire state times out. The
2011 default value is 30 seconds. For auto=ondemand connections and
2012 Opportunistic connections an IPsec policy is installed in the
2013 kernel. If an incoming or outgoing packet matches this policy, a
2014 state is created in the kernel and the kernel sends an ACQUIRE
2015 message to the IKE daemon pluto. While this state is in place, no
2016 new acquires will come in for this connection. The default should
2017 be fine for most people. One use case of shortening these is if
2018 opportunistc encryption is used towards cloud instances that can
2019 quickly re-use IP addresses. This value is only used during the
2020 libreswan startup process by the ipsec _stackmanager helper. See
2021 also failureshunt and negotiationshunt
2022 dumpdir
2024 in what directory should things started by setup (notably the Pluto
2025 daemon) be allowed to dump core? The default value is
2026 /var/run/pluto. When SELinux runs in enforced mode, changing this
2027 requires a similar change in the SELinux policy for the pluto
2028 daemon.
2029 statsbin
2031 This option specifies an optional external program to report tunnel
2032 state changes too. The default is not to report tunnel state
2033 changes. This program can be used to notify the user's desktop
2034 (dbus, NetworkManager) or to report tunnel changes to a central
2035 logging server.
2036 ipsecdir
2038 Specifies a directory for administrator-controlled configuration
2039 files and directories. The default value is /etc/ipsec.d. It may
2040 contain the following files and directories:
2041 passwd
2043 (optional) for XAUTH support if not using PAM (this file should
2044 not be world-readable). See README.XAUTH for more information.
2045 nsspassword
2047 (optional) passwords needed to unlock the NSS database in
2048 /var/lib/ipsec/nss (this file should not be world-readable).
2049 See README.nss for more information.
2050 policies/
2052 a directory containing policy group configuration information.
2053 See POLICY GROUP FILES in this document for more information.
2054 cacerts/
2056 DEPRECATED: a directory to store trust anchors (root
2057 certificate authority certificates). The preferred (and
2058 default) approach is to store CA certs in the NSS database
2059 instead. See README.nss for more information.
2060 crls/
2062 DEPRECATED: a directory to store certificate revocation lists.
2063 The preferred (and default) approach is to store CRLs in the
2064 NSS database instead. See README.nss for more information.
2065 When SELinux runs in enforced mode, changing this requires a
2067 similar change in the SELinux policy for the pluto daemon.
2068 nssdir
2070 Specifies a directory for NSS database files. The default value is
2071 /var/lib/ipsec/nss. It may contain the following files:
2072 pkcs11.txt
2074 Detailed info about NSS database creation parameteres.
2075 cert9.db
2077 NSS Certificate database.
2078 key4.db
2080 NSS Key database.
2081 When SELinux runs in enforced mode, changing this requires a
2083 similar change in the SELinux policy for the pluto daemon.
2084 secretsfile
2086 pathname of the file that stores the secret credentials such as
2087 preshared keys (PSKs). See man ipsec.secrets for the syntax. The
2088 default value is /etc/ipsec.secrets.
2089 seccomp
2091 Set the seccomp kernel syscall whitelisting feature. When set to
2092 enabled, if pluto calls a syscall that is not on the compiled-in
2093 whitelist, the kernel will assume an exploit is attempting to use
2094 pluto for malicious access to the system and terminate the pluto
2095 daemon. When set to tolerant, the kernel will only block the rogue
2096 syscall and pluto will attempt to continue. If set to disabled,
2097 pluto is allowed to call any syscall offered by the kernel,
2098 although it might be restricted via other security mechanisms, such
2099 as capabilities, SElinux, AppArmor or other OS security features.
2100 The current default is disabled, but it is expected that in the
2102 future this feature will be enabled on all supported operating
2103 systems. Similarly, it is expected that further privilege
2104 separation will reduce the allowed syscalls - for example for the
2105 crypto helpers or DNS helpers.
2106 Warning: The restrictions of pluto are inherited by the updown
2108 scripts, so these scripts are also not allowed to use syscalls that
2109 are forbidden for pluto.
2110 This feature can be tested using ipsec whack --seccomp-crashtest.
2112 Warning: With seccomp=enabled, pluto will be terminated by the
2113 kernel. With seccomp=tolerant or seccomp=disabled, pluto will
2114 report the results of the seccomp test. SECCOMP will log the
2115 forbidden syscall numbers to the audit log, but only with
2116 seccomp=enabled. The tool scmp_sys_resolver from the libseccomp
2117 development package can be used to translate the syscall number
2118 into a name. See programs/pluto/pluto_seccomp.c for the list of
2119 allowed syscalls.
2120 dnssec-enable
2122 Whether pluto should perform dnssec validation using libunbound,
2123 provided libreswan was compiled with USE_DNSSEC. A value of yes
2124 (the default) means pluto should perform DNSSEC validation. Note
2125 that pluto reads the file /etc/resolv.conf to determine which
2126 nameservers to use.
2127 dnssec-rootkey-file
2129 The location of the DNSSEC root zone public key file. The default
2130 is /var/lib/unbound/root.key but this can be changed at compile
2131 time.
2132 dnssec-anchors
2134 The location of a file containing additional DNSSEC Trust Anchors.
2135 This can be used when a network is using split-DNS and the internal
2136 hierarchy is using DNSSEC trust anchors. There is no default value.
2137
2139 For Opportunistic connections, the system requires creating special
2140 named conns that are used to implement the default policy groups.
2141 Currently, these names cannot be changed.
2142 conn clear
2145 type=passthrough
2146 authby=never
2147 left=%defaultroute
2148 right=%group
2149 auto=route
2150 conn clear-or-private
2152 type=passthrough
2153 left=%defaultroute
2154 leftid=%myid
2155 right=%opportunisticgroup
2156 failureshunt=passthrough
2157 keyingtries=3
2158 ikelifetime=1h
2159 salifetime=1h
2160 rekey=no
2161 auto=route
2162 conn private-or-clear
2164 type=tunnel
2165 left=%defaultroute
2166 leftid=%myid
2167 right=%opportunisticgroup
2168 failureshunt=passthrough
2169 keyingtries=3
2170 ikelifetime=1h
2171 salifetime=1h
2172 rekey=no
2173 auto=route
2174 conn private
2176 type=tunnel
2177 left=%defaultroute
2178 leftid=%myid
2179 right=%opportunisticgroup
2180 failureshunt=drop
2181 keyingtries=3
2182 ikelifetime=1h
2183 salifetime=1h
2184 rekey=no
2185 auto=route
2186 conn block
2188 type=reject
2189 authby=never
2190 left=%defaultroute
2191 right=%group
2192 auto=route
2193 These conns will only work if %defaultroute works. The leftid will be
2196 the interfaces IP address by default, but it can also be set to
2197 %fromcert or use a DNS name.
2198
2200 The optional files under /etc/ipsec.d/policies, including
2201 /etc/ipsec.d/policies/clear
2204 /etc/ipsec.d/policies/clear-or-private
2205 /etc/ipsec.d/policies/private-or-clear
2206 /etc/ipsec.d/policies/private
2207 /etc/ipsec.d/policies/block
2208 may contain policy group configuration information to supplement
2211 ipsec.conf. Their contents are not security-sensitive.
2212 These files are text files. Each consists of a list of CIDR blocks, one
2214 per line. White space followed by # followed by anything to the end of
2215 the line is a comment and is ignored, as are empty lines.
2216 A connection in ipsec.conf that has right=%group or
2218 right=%opportunisticgroup is a policy group connection. When a policy
2219 group file of the same name is loaded at system start, the connection
2220 is instantiated such that each CIDR block serves as an instance's right
2221 value. The system treats the resulting instances as normal connections.
2222 For example, given a suitable connection definition private, and the
2224 file /etc/ipsec.d/policies/private with an entry 192.0.2.3, the system
2225 creates a connection instance private#192.0.2.3. This connection
2226 inherits all details from private, except that its right client is
2227 192.0.2.3.
2228
2230 The standard Libreswan install includes several policy groups which
2231 provide a way of classifying possible peers into IPsec security
2232 classes: private (talk encrypted only), private-or-clear (prefer
2233 encryption), clear-or-private (respond to requests for encryption),
2234 clear and block.
2235
2237 When choosing a connection to apply to an outbound packet caught with a
2238 %trap, the system prefers the one with the most specific eroute that
2239 includes the packet's source and destination IP addresses. Source
2240 subnets are examined before destination subnets. For initiating, only
2241 routed connections are considered. For responding, unrouted but added
2242 connections are considered.
2243 When choosing a connection to use to respond to a negotiation that
2245 doesn't match an ordinary conn, an opportunistic connection may be
2246 instantiated. Eventually, its instance will be /32 -> /32, but for
2247 earlier stages of the negotiation, there will not be enough information
2248 about the client subnets to complete the instantiation.
2249
2251 /etc/ipsec.conf
2252 /etc/ipsec.d/policies/clear
2253 /etc/ipsec.d/policies/clear-or-private
2254 /etc/ipsec.d/policies/private-or-clear
2255 /etc/ipsec.d/policies/private
2256 /etc/ipsec.d/policies/block
2257
2259 ipsec(8), ipsec_auto(8), ipsec_rsasigkey(8)
2260
2262 Designed for the FreeS/WAN project <https://www.freeswan.org> by Henry
2263 Spencer.
2264
2266 Before reporting new bugs, please ensure you are using the latest
2267 version of Libreswan.
2268 When type or failureshunt is set to drop or reject, Libreswan blocks
2270 outbound packets using eroutes, but assumes inbound blocking is handled
2271 by the firewall. Libreswan offers firewall hooks via an “updown”
2272 script. However, the default ipsec _updown provides no help in
2273 controlling a modern firewall.
2274 Including attributes of the keying channel (authentication methods,
2276 ikelifetime, etc.) as an attribute of a connection, rather than of a
2277 participant pair, is dubious and incurs limitations.
2278 The use of %any with the protoport= option is ambiguous. Should the SA
2280 permits any port through or should the SA negotiate any single port
2281 through? The first is a basic conn with a wildcard. The second is a
2282 template. The second is the current behaviour, and it's wrong for quite
2283 a number of uses involving TCP. The keyword %one may be introduced in
2284 the future to separate these two cases.
2285 It would be good to have a line-continuation syntax, especially for the
2287 very long lines involved in RSA signature keys.
2288 The ability to specify different identities, authby, and public keys
2290 for different automatic-keyed connections between the same participants
2291 is misleading; this doesn't work dependably because the identity of the
2292 participants is not known early enough. This is especially awkward for
2293 the “Road Warrior” case, where the remote IP address is specified as
2294 0.0.0.0, and that is considered to be the “participant” for such
2295 connections.
2296 If conns are to be added before DNS is available, left=FQDN,
2298 leftnextop=FQDN, and leftrsasigkey=%dnsonload will fail.
2299 ipsec_pluto(8) does not actually use the public key for our side of a
2300 conn but it isn't generally known at a add-time which side is ours
2301 (Road Warrior and Opportunistic conns are currently exceptions).
2302 The myid option does not affect explicit
2304 ipsec auto --add or ipsec auto --replace commands for implicit conns.
2305
2307 Paul Wouters
2308 documenter
2309libreswan 09/08/2023 IPSEC.CONF(5)