1IPSEC.CONF(5) [FIXME: manual] IPSEC.CONF(5)
2
6 ipsec.conf - IPsec configuration and connections
7
9 The optional ipsec.conf file specifies most configuration and control
10 information for the Openswan IPsec subsystem. (The major exception is
11 secrets for authentication; see ipsec.secrets(5).) Its contents are not
12 security-sensitive unless manual keying is being done for more than
13 just testing, in which case the encryption/authentication keys in the
14 descriptions for the manually-keyed connections are very sensitive (and
15 those connection descriptions are probably best kept in a separate
16 file, via the include facility described below).
17 The file is a text file, consisting of one or more sections. White
19 space followed by # followed by anything to the end of the line is a
20 comment and is ignored, as are empty lines which are not within a
21 section.
22 A line which contains include and a file name, separated by white
24 space, is replaced by the contents of that file, preceded and followed
25 by empty lines. If the file name is not a full pathname, it is
26 considered to be relative to the directory containing the including
27 file. Such inclusions can be nested. Only a single filename may be
28 supplied, and it may not contain white space, but it may include shell
29 wildcards (see sh(1)); for example:
30 include ipsec.*.conf
32 The intention of the include facility is mostly to permit keeping
34 information on connections, or sets of connections, separate from the
35 main configuration file. This permits such connection descriptions to
36 be changed, copied to the other security gateways involved, etc.,
37 without having to constantly extract them from the configuration file
38 and then insert them back into it. Note also the also and alsoflip
39 parameters (described below) which permit splitting a single logical
40 section (e.g. a connection description) into several actual sections.
41 The first significant line of the file must specify the version of this
43 specification that it conforms to:
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 which 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 which 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 which 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 which
106 does not have a parameter of the same name gets a copy of the one from
107 the %default section. There may be multiple %default sections of a
108 given type, but only one default may be supplied for any specific
109 parameter name, and all %default sections of a given type must precede
110 all non-%default sections of that type. %default sections may not
111 contain also or alsoflip parameters.
112 Currently there are two types of section: a config section specifies
114 general configuration information for IPsec, while a conn section
115 specifies an IPsec connection.
116
118 A conn section contains a connection specification, defining a network
119 connection to be made using IPsec. The name given is arbitrary, and is
120 used to identify the connection to ipsec_auto(8) and ipsec_manual(8).
121 Here's a simple example:
122 conn snt
125 left=10.11.11.1
126 leftsubnet=10.0.1.0/24
127 leftnexthop=172.16.55.66
128 leftsourceip=10.0.1.1
129 right=192.168.22.1
130 rightsubnet=10.0.2.0/24
131 rightnexthop=172.16.88.99
132 rightsourceip=10.0.2.1
133 keyingtries=%forever
134 A note on terminology... In automatic keying, there are two kinds of
136 communications going on: transmission of user IP packets, and
137 gateway-to-gateway negotiations for keying, rekeying, and general
138 control. The data path (a set of “IPsec SAs”) used for user packets is
139 herein referred to as the “connection”; the path used for negotiations
140 (built with “ISAKMP SAs”) is referred to as the “keying channel”.
141 To avoid trivial editing of the configuration file to suit it to each
143 system involved in a connection, connection specifications are written
144 in terms of left and right participants, rather than in terms of local
145 and remote. Which participant is considered left or right is arbitrary;
146 IPsec figures out which one it is being run on based on internal
147 information. This permits using identical connection specifications on
148 both ends. There are cases where there is no symmetry; a good
149 convention is to use left for the local side and right for the remote
150 side (the first letters are a good mnemonic).
151 Many of the parameters relate to one participant or the other; only the
153 ones for left are listed here, but every parameter whose name begins
154 with left has a right counterpart, whose description is the same but
155 with left and right reversed.
156 Parameters are optional unless marked “(required)”; a parameter
158 required for manual keying need not be included for a connection which
159 will use only automatic keying, and vice versa.
160 CONN PARAMETERS: GENERAL
162 The following parameters are relevant to both automatic and manual
163 keying. Unless otherwise noted, for a connection to work, in general it
164 is necessary for the two ends to agree exactly on the values of these
165 parameters.
166 connaddrfamily
168 the connection addrress family of the connection; currently the
169 accepted values are ipv4 (the default); or ipv6,
170 The ipv6 family is currently only supported using the NETKEY stack.
172 type
174 the type of the connection; currently the accepted values are
175 tunnel (the default) signifying a host-to-host, host-to-subnet, or
176 subnet-to-subnet tunnel; transport, signifying host-to-host
177 transport mode; passthrough, signifying that no IPsec processing
178 should be done at all; drop, signifying that packets should be
179 discarded; and reject, signifying that packets should be discarded
180 and a diagnostic ICMP returned.
181 left
183 (required) the IP address of the left participant's public-network
184 interface, in any form accepted by ipsec_ttoaddr(3). Currently,
185 IPv4 and IPv6 IP addresses are supported. There are several magic
186 values. If it is %defaultroute, and the config setup section's,
187 interfaces specification contains %defaultroute, left will be
188 filled in automatically with the local address of the default-route
189 interface (as determined at IPsec startup time); this also
190 overrides any value supplied for leftnexthop. (Either left or right
191 may be %defaultroute, but not both.) The value %any signifies an
192 address to be filled in (by automatic keying) during negotiation.
193 The value %opportunistic signifies that both left and leftnexthop
194 are to be filled in (by automatic keying) from DNS data for left's
195 client. The value can also contain the interface name, which will
196 then later be used to obtain the IP address from to fill in. For
197 example %ppp0 The values %group and %opportunisticgroup makes this
198 a policy group conn: one that will be instantiated into a regular
199 or opportunistic conn for each CIDR block listed in the policy
200 group file with the same name as the conn.
201 If using IP addresses in combination with NAT, always use the
203 actual local machine's (NAT'ed) IP address, and if the remote (eg
204 right=) is NAT'ed as well, the remote's public (not NAT'ed) IP
205 address. Note that this makes the configuration no longer
206 symmetrical on both sides, so you cannot use an identical
207 configuration file on both hosts.
208 leftsubnet
210 private subnet behind the left participant, expressed as
211 network/netmask (actually, any form acceptable to
212 ipsec_ttosubnet(3)); Currentlly, IPv4 and IPv6 ranges are
213 supported. if omitted, essentially assumed to be left/32,
214 signifying that the left end of the connection goes to the left
215 participant only
216 It supports two magic shorthands vhost: and vnet:, which can list
218 subnets in the same syntax as virtual_private. The value %priv
219 expands to the networks specified in virtual_private. The value %no
220 means no subnet. A common use for allowing roadwarrios to come in
221 on public IPs or via accepted NATed networks from RFC1918 is to use
222 leftsubnet=vhost:%no,%priv. The vnet: option can be used to allow
223 RFC1918 subnets without hardcoding them. When using vnet the
224 connection will instantiate, allowing for multiple tunnels with
225 different subnets.
226 leftsubnets
228 specify multiple private subnets behind the left participant,
229 expressed as { networkA/netmaskA networkB/netmaskB [...] } If both
230 a leftsubnets= and rightsubnets= is defined, all combinations of
231 subnet tunnels will be instantiated. You cannot use leftsubnet and
232 leftsubnets together. For examples see testing/pluto/multinet-*.
233 leftprotoport
235 allowed protocols and ports over connection, also called Port
236 Selectors. The argument is in the form protocol, which can be a
237 number or a name that will be looked up in /etc/protocols, such as
238 leftprotoport=icmp, or in the form of protocol/port, such as
239 tcp/smtp. Ports can be defined as a number (eg. 25) or as a name
240 (eg smtp) which will be looked up in /etc/services. A special
241 keyword %any can be used to allow all ports of a certain protocol.
242 The most common use of this option is for L2TP connections to only
243 allow l2tp packets (UDP port 1701), eg: leftprotoport=17/1701. Some
244 clients, notably older Windows XP and some Mac OSX clients, use a
245 random high port as source port. In those cases
246 rightprotoport=17/%any can be used to allow all UDP traffic on the
247 connection. Note that this option is part of the proposal, so it
248 cannot be arbitrarily left out if one end does not care about the
249 traffic selection over this connection - both peers have to agree.
250 The Port Selectors show up in the output of ipsec eroute and ipsec
251 auto --status eg:"l2tp":
252 193.110.157.131[@aivd.xelernace.com]:7/1701...%any:17/1701 This
253 option only filters outbound traffic. Inbound traffic selection
254 must still be based on firewall rules activated by an updown
255 script. The variablees $PLUTO_MY_PROTOCOL, $PLUTO_PEER_PROTOCOL,
256 $PLUTO_MY_PORT, and $PLUTO_PEER_PORT are available for use in
257 updown scripts. Older workarounds for bugs involved a setting of
258 17/0 to denote any single UDP port (not UDP port 0). Some clients,
259 most notably OSX, uses a random high port, instead of port 1701 for
260 L2TP.
261 leftnexthop
263 next-hop gateway IP address for the left participant's connection
264 to the public network; defaults to %direct (meaning right). If the
265 value is to be overridden by the left=%defaultroute method (see
266 above), an explicit value must not be given. If that method is not
267 being used, but leftnexthop is %defaultroute, and
268 interfaces=%defaultroute is used in the config setup section, the
269 next-hop gateway address of the default-route interface will be
270 used. The magic value %direct signifies a value to be filled in (by
271 automatic keying) with the peer's address. Relevant only locally,
272 other end need not agree on it.
273 leftsourceip
275 the IP address for this host to use when transmitting a packet to
276 the other side of this link. Relevant only locally, the other end
277 need not agree. This option is used to make the gateway itself use
278 its internal IP, which is part of the leftsubnet, to communicate to
279 the rightsubnet or right. Otherwise, it will use its nearest IP
280 address, which is its public IP address. This option is mostly used
281 when defining subnet-subnet connections, so that the gateways can
282 talk to each other and the subnet at the other end, without the
283 need to build additional host-subnet, subnet-host and host-host
284 tunnels. Both IPv4 and IPv6 addresses are supported.
285 leftupdown
287 what “updown” script to run to adjust routing and/or firewalling
288 when the status of the connection changes (default ipsec _updown).
289 May include positional parameters separated by white space
290 (although this requires enclosing the whole string in quotes);
291 including shell metacharacters is unwise. An example to enable
292 routing when using the NETKEY stack, one can use:
293 leftupdown="ipsec _updown --route yes"
295 See ipsec_pluto(8) for details. Relevant only locally, other end
297 need not agree on it.
298 leftfirewall
300 This option is obsolete and should not used anymore.
301 If one or both security gateways are doing forwarding firewalling
303 (possibly including masquerading), and this is specified using the
304 firewall parameters, tunnels established with IPsec are exempted from
305 it so that packets can flow unchanged through the tunnels. (This means
306 that all subnets connected in this manner must have distinct,
307 non-overlapping subnet address blocks.) This is done by the default
308 updown script (see ipsec_pluto(8)).
309 The implementation of this makes certain assumptions about firewall
311 setup, and the availability of the Linux Advanced Routing tools. In
312 situations calling for more control, it may be preferable for the user
313 to supply his own updown script, which makes the appropriate
314 adjustments for his system.
315 CONN PARAMETERS: AUTOMATIC KEYING
317 The following parameters are relevant only to automatic keying, and are
318 ignored in manual keying. Unless otherwise noted, for a connection to
319 work, in general it is necessary for the two ends to agree exactly on
320 the values of these parameters.
321 auto
323 what operation, if any, should be done automatically at IPsec
324 startup; currently-accepted values are add (signifying an ipsec
325 auto --add), route (signifying that plus an ipsec auto --route),
326 start (signifying that plus an ipsec auto --up), manual (signifying
327 an ipsec manual --up), and ignore (also the default) (signifying no
328 automatic startup operation). See the config setup discussion
329 below. Relevant only locally, other end need not agree on it (but
330 in general, for an intended-to-be-permanent connection, both ends
331 should use auto=start to ensure that any reboot causes immediate
332 renegotiation).
333 authby
335 how the two security gateways should authenticate each other;
336 acceptable values are secret for shared secrets, rsasig for RSA
337 digital signatures (the default), secret|rsasig for either, and
338 never if negotiation is never to be attempted or accepted (useful
339 for shunt-only conns). Digital signatures are superior in every way
340 to shared secrets.
341 ike
343 IKE encryption/authentication algorithm to be used for the
344 connection (phase 1 aka ISAKMP SA). The format is
345 "cipher-hash;modpgroup, cipher-hash;modpgroup, ..." Any left out
346 option will be filled in with all allowed default options. Multiple
347 proposals are separated by a comma. If an ike= line is specified,
348 no other received proposals will be accepted. Formerly there was a
349 distinction (by using a "!" symbol) between "strict mode" or not.
350 That mode has been obsoleted. If an ike= option is specified, the
351 mode is always strict, meaning no other received proposals will be
352 accepted. Some examples are ike=3des-sha1,aes-sha1, ike=aes,
353 ike=aes128-md5;modp2048, ike=aes128-sha1;dh22,
354 ike=3des-md5;modp1024,aes-sha1;modp1536 or ike=modp1536. The
355 options must be suitable as a value of ipsec_spi(8)'s --ike option.
356 The default is to use IKE, and to allow all combinations of:
357 cipher: 3des or aes
359 hash: sha1 or md5
360 pfsgroup (DHgroup): modp1024 or modp1536
361 If Openswan was compiled with extra INSECURE and BROKEN options,
363 then the des (1des) and null cipher, as well as modp768 are
364 available. This turns your VPN into a joke. Do not enable these
365 options.
366 If openswan was compiled with USE_MODP_RFC5114 support, then
368 Diffie-Hellman groups 22, 23 and 24 are also implemented as per
369 RFC-5114. Instead of the modp key syntax, use the "dh" keyword, for
370 example ike=3des-sha1;dh23
371 phase2
373 Sets the type of SA that will be produced. Valid options are: esp
374 for encryption (the default), and ah for authentication only.
375 phase2alg
377 Specifies the algorithms that will be offered/accepted for a phase2
378 negotiation. If not specified, a secure set of defaults will be
379 used. Sets are separated using comma's.
380 The default values are the same as for ike= Note also that not all
382 ciphers available to the kernel (eg through CryptoAPI) are
383 necessarilly supported here.
384 The format for ESP is ENC-AUTH followed by an optional PFSgroup.
386 For instance, "3des-md5" or "aes256-sha1;modp2048" or
387 "aes-sha1,aes-md5".
388 For RFC-5114 DH groups, use the "dh" keyword, eg "aes256-sha1;dh23"
390 The format for AH is AUTH followed by an optional PFSgroup. For
392 instance, "md5" or "sha1;modp1536".
393 A special case is AES CCM, which uses the syntax of
395 "phase2alg=aes_ccm_a-152-null"
396 esp
398 This option is obsolete. Please use phase2alg instead.
399 ah
401 AH authentication algorithm to be used for the connection, e.g
402 here. hmac-md5 The options must be suitable as a value of
403 ipsec_spi(8)'s --ah option. The default is not to use AH. If for
404 some (invalid) reason you still think you need AH, please use esp
405 with the null encryption cipher instead. Note also that not all
406 ciphers available to the kernel (eg through CryptoAPI) are
407 necessarilly supported here.
408 ikev2
410 IKEv2 (RFC4309) settings to be used. Currently the accepted values
411 are permit, (the default) signifying no IKEv2 should be
412 transmitted, but will be accepted if the other ends initiates to us
413 with IKEv2; never or no signifying no IKEv2 negotiation should be
414 transmitted or accepted; propose or yes signifying that we permit
415 IKEv2, and also use it as the default to initiate; insist,
416 signifying we only accept and receive IKEv2 - IKEv1 negotiations
417 will be rejected.
418 If the ikev2= setting is set to permit or propose, Openswan will
420 try and detect a "bid down" attack from IKEv2 to IKEv1. Since there
421 is no standard for transmitting the IKEv2 capability with IKEv1,
422 Openswan uses a special Vendor ID "CAN-IKEv2". If a fall back from
423 IKEv2 to IKEv1 was detected, and the IKEv1 negotiation contains
424 Vendor ID "CAN-IKEv2", Openswan will immediately attempt and IKEv2
425 rekey and refuse to use the IKEv1 connection. With an ikev2=
426 setting of insist, no IKEv1 negotiation is allowed, and no bid down
427 attack is possible.
428 sareftrack
430 Set the method of tracking reply packets with SArefs when using an
431 SAref compatible stack. Currently only the mast stack supports
432 this. Acceptable values are yes (the default), no or conntrack.
433 This option is ignored when SArefs are not supported. This option
434 is passed as PLUTO_SAREF_TRACKING to the updown script which makes
435 the actual decisions whether to perform any iptables/ip_conntrack
436 manipulation. A value of yes means that an IPSEC mangle table will
437 be created. This table will be used to match reply packets. A value
438 of conntrack means that additionally, subsequent packets using this
439 connection will be marked as well, reducing the lookups needed to
440 find the proper SAref by using the ip_conntrack state. A value of
441 no means no IPSEC mangle table is created, and SAref tracking is
442 left to a third-party (kernel) module. In case of a third party
443 module, the SArefs can be relayed using the HAVE_STATSD deamon.
444 leftid
446 how the left participant should be identified for authentication;
447 defaults to left. Can be an IP address (in any ipsec_ttoaddr(3)
448 syntax) or a fully-qualified domain name preceded by @ (which is
449 used as a literal string and not resolved). The magic value
450 %fromcert causes the ID to be set to a DN taken from a certificate
451 that is loaded. Prior to 2.5.16, this was the default if a
452 certificate was specified. The magic value %none sets the ID to no
453 ID. This is included for completeness, as the ID may have been set
454 in the default conn, and one wishes for it to default instead of
455 being explicitly set. The magic value %myid stands for the current
456 setting of myid. This is set in config setup or by ipsec_whack(8)),
457 or, if not set, it is the IP address in %defaultroute (if that is
458 supported by a TXT record in its reverse domain), or otherwise it
459 is the system's hostname (if that is supported by a TXT record in
460 its forward domain), or otherwise it is undefined.
461 leftrsasigkey
463 the left participant's public key for RSA signature authentication,
464 in RFC 2537 format using ipsec_ttodata(3) encoding. The magic value
465 %none means the same as not specifying a value (useful to override
466 a default). The value %dnsondemand (the default) means the key is
467 to be fetched from DNS at the time it is needed. The value
468 %dnsonload means the key is to be fetched from DNS at the time the
469 connection description is read from ipsec.conf; currently this will
470 be treated as %none if right=%any or right=%opportunistic. The
471 value %dns is currently treated as %dnsonload but will change to
472 %dnsondemand in the future. The identity used for the left
473 participant must be a specific host, not %any or another magic
474 value. The value %cert will load the information required from a
475 certificate defined in %leftcert and automatically define leftid
476 for you. Caution: if two connection descriptions specify different
477 public keys for the same leftid, confusion and madness will ensue.
478 leftrsasigkey2
480 if present, a second public key. Either key can authenticate the
481 signature, allowing for key rollover.
482 leftcert
484 If you are using leftrsasigkey=%cert this defines the certificate
485 you would like to use. It should point to a X.509 encoded
486 certificate file. If you do not specify a full pathname, by default
487 it will look in /etc/ipsec.d/certs. If openswan has been compiled
488 with USE_LIBNSS=true, then openswan will also check the NSS
489 database for RSA keys. These can be software or hardware.
490 leftca
492 specifies the authorized Certificate Authority (CA) that signed the
493 certificate of the peer. If undefined, it defaults to the CA that
494 signed the certificate specified in leftcert. The special
495 rightca=%same is implied when not specifying a rightca and means
496 that only peers with certificates signed by the same CA as the
497 leftca will be allowed. This option is only useful in complex multi
498 CA certificate situations. When using a single CA, it can be safely
499 omitted for both left and right.
500 leftsendcert
502 This option configures when Openswan will send X.509 certificates
503 to the remote host. Acceptable values are yes|always (signifying
504 that we should always send a certificate), ifasked (signifying that
505 we should send a certificate if the remote end asks for it), and
506 no|never (signifying that we will never send a X.509 certificate).
507 The default for this option is ifasked which may break
508 compatibility with other vendor's IPSec implementations, such as
509 Cisco and SafeNet. If you find that you are getting errors about no
510 ID/Key found, you likely need to set this to always. This per-conn
511 option replaces the obsolete global nocrsend option.
512 leftxauthserver
514 Left is an XAUTH server. This can use PAM for authentication or md5
515 passwords in /etc/ipsec.d/passwd. These are additional credentials
516 to verify the user identity, and should not be confused with the
517 XAUTH group secret, which is just a regular PSK defined in
518 ipsec.secrets. The other side of the connection should be
519 configured as rightxauthclient. XAUTH connections cannot rekey, so
520 rekey=no should be specified in this conn. For further details on
521 how to compile and use XAUTH, see README.XAUTH. Acceptable values
522 are yes or no (the default).
523 leftxauthclient
525 Left is an XAUTH client. The xauth connection will have to be
526 started interactively and cannot be configured using auto=start.
527 Instead, it has to be started from the commandline using ipsec auto
528 --up connname. You will then be prompted for the username and
529 password. To setup an XAUTH connection non-interactively, which
530 defeats the whole purpose of XAUTH, but is regularly requested by
531 users, it is possible to use a whack command - ipsec whack --name
532 baduser --ipsecgroup-xauth --xauthname badusername --xauthpass
533 password --initiate The other side of the connection should be
534 configured as rightxauthserver. Acceptable values are yes or no
535 (the default).
536 leftxauthusername
538 The XAUTH username associated with this XAUTH connection. The XAUTH
539 password can be configured in the ipsec.secrets file.
540 leftmodecfgserver
542 Left is a Mode Config server. It can push network configuration to
543 the client. Acceptable values are yes or no (the default).
544 leftmodecfgclient
546 Left is a Mode Config client. It can receive network configuration
547 from the server. Acceptable values are yes or no (the default).
548 modecfgpull
550 Pull the Mode Config network information from the server.
551 Acceptable values are yes or no (the default).
552 modecfgdns1, modecfgdns2, modecfgwins1, modecfgwins2
554 Specify the IP address for DNS or WINS servers for the client to
555 use.
556 remote_peer_type
558 Set the remote peer type. This can enable additional processing
559 during the IKE negotiation. Acceptable values are cisco or ietf
560 (the default). When set to cisco, support for Cisco IPsec gateway
561 redirection and Cisco obtained DNS and domainname are enabled. This
562 includes automatically updating (and restoring) /etc/resolv.conf.
563 These options require that XAUTH is also enabled on this
564 connection.
565 nm_configured
567 Mark this connection as controlled by Network Manager. Acceptable
568 values are yes or no (the default). Currently, setting this to yes
569 will cause openswan to skip reconfiguring resolv.conf when used
570 with XAUTH and ModeConfig.
571 forceencaps
573 In some cases, for example when ESP packets are filtered or when a
574 broken IPsec peer does not properly recognise NAT, it can be useful
575 to force RFC-3948 encapsulation. forceencaps=yes forces the NAT
576 detection code to lie and tell the remote peer that RFC-3948
577 encapsulation (ESP in UDP port 4500 packets) is required. For this
578 option to have any effect, the setup section option
579 nat_traversal=yes needs to be set. Acceptable values are yes or no
580 (the default).
581 overlapip
583 a boolean (yes/no) that determines, when *subnet=vhost: is used, if
584 the virtual IP claimed by this states created from this connection
585 can with states created from other connections.
586 Note that connection instances created by the Opportunistic
588 Encryption or PKIX (x.509) instantiation system are distinct
589 internally. They will inherit this policy bit.
590 The default is no.
592 This feature is only available with kernel drivers that support SAs
594 to overlapping conns. At present only the (klips)mast protocol
595 stack supports this feature.
596 dpddelay
598 Set the delay (in seconds) between Dead Peer Dectection (RFC 3706)
599 keepalives (R_U_THERE, R_U_THERE_ACK) that are sent for this
600 connection (default 30 seconds). If dpddelay is set, dpdtimeout
601 also needs to be set.
602 dpdtimeout
604 Set the length of time (in seconds) we will idle without hearing
605 either an R_U_THERE poll from our peer, or an R_U_THERE_ACK reply.
606 After this period has elapsed with no response and no traffic, we
607 will declare the peer dead, and remove the SA (default 120
608 seconds). If dpdtimeout is set, dpdaction also needs to be set.
609 dpdaction
611 When a DPD enabled peer is declared dead, what action should be
612 taken. hold (default) means the eroute will be put into %hold
613 status, while clear means the eroute and SA with both be cleared.
614 restart means the the SA will immediately be renegotiated, and
615 restart_by_peer means that ALL SA's to the dead peer will
616 renegotiated.
617 dpdaction=clear is really only useful on the server of a Road
619 Warrior config.
620 pfs
622 whether Perfect Forward Secrecy of keys is desired on the
623 connection's keying channel (with PFS, penetration of the
624 key-exchange protocol does not compromise keys negotiated earlier);
625 Since there is no reason to ever refuse PFS, Openswan will allow a
626 connection defined with pfs=no to use PFS anyway. Acceptable values
627 are yes (the default) and no.
628 pfsgroup
630 This option is obsoleted, please use phase2alg if you need the pfs
631 to be different from phase1 (the default) using:
632 phase2alg=aes128-md5;modp1024
633 aggrmode
635 Use Aggressive Mode instead of Main Mode. Aggressive Mode is less
636 secure, and vulnerable to Denial Of Service attacks. It is also
637 vulnerable to brute force attacks with software such as ikecrack.
638 It should not be used, and it should especially not be used with
639 XAUTH and group secrets (PSK). If the remote system administrator
640 insists on staying irresponsible, enable this option.
641 Aggressive Mode is further limited to only proposals with one DH
643 group as there is no room to negotiate the DH group. Therefor it is
644 mandatory for Aggressive Mode connections that both ike= and
645 phase2alg= options are specified with only fully specified proposal
646 using one DH group. Acceptable values are yes or no (the default).
647 The ISAKMP SA is created in exchange 1 in aggressive mode. Openswan
649 has to send the exponent during that exchange, so it has to know
650 what DH group to use before starting. This is why you can not have
651 multiple DH groups in aggressive mode. In IKEv2, which uses a
652 similar method to IKEv1 Aggressive Mode, there is a message to
653 convey the DH group is wrong, and so an IKEv2 connection can
654 actually recover from picking the wrong DH group by restarting its
655 negotiation.
656 salifetime
658 how long a particular instance of a connection (a set of
659 encryption/authentication keys for user packets) should last, from
660 successful negotiation to expiry; acceptable values are an integer
661 optionally followed by s (a time in seconds) or a decimal number
662 followed by m, h, or d (a time in minutes, hours, or days
663 respectively) (default 8h, maximum 24h). Normally, the connection
664 is renegotiated (via the keying channel) before it expires. The two
665 ends need not exactly agree on salifetime, although if they do not,
666 there will be some clutter of superseded connections on the end
667 which thinks the lifetime is longer.
668 The keywords "keylife" and "lifetime" are aliases for "salifetime."
670 rekey
672 whether a connection should be renegotiated when it is about to
673 expire; acceptable values are yes (the default) and no. The two
674 ends need not agree, but while a value of no prevents Pluto from
675 requesting renegotiation, it does not prevent responding to
676 renegotiation requested from the other end, so no will be largely
677 ineffective unless both ends agree on it.
678 rekeymargin
680 how long before connection expiry or keying-channel expiry should
681 attempts to negotiate a replacement begin; acceptable values as for
682 salifetime (default 9m). Relevant only locally, other end need not
683 agree on it.
684 rekeyfuzz
686 maximum percentage by which rekeymargin should be randomly
687 increased to randomize rekeying intervals (important for hosts with
688 many connections); acceptable values are an integer, which may
689 exceed 100, followed by a `%' (default set by ipsec_pluto(8),
690 currently 100%). The value of rekeymargin, after this random
691 increase, must not exceed salifetime. The value 0% will suppress
692 time randomization. Relevant only locally, other end need not agree
693 on it.
694 keyingtries
696 how many attempts (a whole number or %forever) should be made to
697 negotiate a connection, or a replacement for one, before giving up
698 (default %forever). The value %forever means “never give up”
699 (obsolete: this can be written 0). Relevant only locally, other end
700 need not agree on it.
701 ikelifetime
703 how long the keying channel of a connection (buzzphrase: “ISAKMP
704 SA”) should last before being renegotiated; acceptable values as
705 for keylife (default set by ipsec_pluto(8), currently 1h, maximum
706 24h). The two-ends-disagree case is similar to that of keylife.
707 compress
709 whether IPComp compression of content is proposed on the connection
710 (link-level compression does not work on encrypted data, so to be
711 effective, compression must be done before encryption); acceptable
712 values are yes and no (the default). The two ends need not agree. A
713 value of yes causes IPsec to propose both compressed and
714 uncompressed, and prefer compressed. A value of no prevents IPsec
715 from proposing compression; a proposal to compress will still be
716 accepted.
717 metric
719 Set the metric for the routes to the ipsecX or mastX interface.
720 This makes it possible to do host failover from another interface
721 to ipsec using route management. This value is passed to the
722 _updown scripts as PLUTO_METRIC. This option is only available with
723 KLIPS or MAST on Linux. Acceptable values are positive numbers,
724 with the default being 1.
725 mtu
727 Set the mtu for the route(s) to the remote endpoint and/or subnets.
728 This is sometimes required when the overhead of the IPsec
729 encapsultion would cause the packet the become too big for a router
730 on the path. Since IPsec cannot trust any unauthenticated ICMP
731 messages, PATH MTU discovery does not work. This can also be needed
732 when using "6to4" IPV6 deployments, which adds another header on
733 the packet size. Acceptable values are positive numbers. There is
734 no default.
735 disablearrivalcheck
737 whether KLIPS's normal tunnel-exit check (that a packet emerging
738 from a tunnel has plausible addresses in its header) should be
739 disabled; acceptable values are yes and no (the default).
740 Tunnel-exit checks improve security and do not break any normal
741 configuration. Relevant only locally, other end need not agree on
742 it.
743 failureshunt
745 what to do with packets when negotiation fails. The default is
746 none: no shunt; passthrough, drop, and reject have the obvious
747 meanings.
748 CONN PARAMETERS: MANUAL KEYING
750 This command was obsoleted around the same time that Al Gore invented
751 the internet. ipsec manual was used in the jurassic period to load
752 static keys into the kernel. There are no rational reasons to use this,
753 and it is not supported anymore. If you need to create static SAs, then
754 you can use ipsec spi and ipsec eroute when using KLIPS or ip xfrm or
755 setkey when using NETKEY.
756 No rational person uses static keys. They are not easier to use.
758 REPEAT: they are not easier to use.
759
761 At present, the only config section known to the IPsec software is the
762 one named setup, which contains information used when the software is
763 being started (see ipsec_setup(8)). Here's an example:
764 config setup
767 interfaces="ipsec0=eth1 ipsec1=ppp0"
768 klipsdebug=none
769 plutodebug=control
770 protostack=auto
771 manualstart=
772 Parameters are optional unless marked “(required)”.
774 The currently-accepted parameter names in a config setup section are:
776 myid
778 the identity to be used for %myid. %myid is used in the implicit
779 policy group conns and can be used as an identity in explicit
780 conns. If unspecified, %myid is set to the IP address in
781 %defaultroute (if that is supported by a TXT record in its reverse
782 domain), or otherwise the system's hostname (if that is supported
783 by a TXT record in its forward domain), or otherwise it is
784 undefined. An explicit value generally starts with ``@''.
785 protostack
787 decide which protocol stack is going to be used. Valid values are
788 "auto", "klips", "netkey" and "mast". The "mast" stack is a
789 variation for the klips stack.
790 interfaces
792 virtual and physical interfaces for IPsec to use: a single
793 virtual=physical pair, a (quoted!) list of pairs separated by white
794 space, or %none. One of the pairs may be written as %defaultroute,
795 which means: find the interface d that the default route points to,
796 and then act as if the value was ``ipsec0=d''. %defaultroute is
797 the default; %none must be used to denote no interfaces, or when
798 using the NETKEY stack. If %defaultroute is used (implicitly or
799 explicitly) information about the default route and its interface
800 is noted for use by ipsec_manual(8) and ipsec_auto(8).)
801 listen
803 IP address to listen on (default depends on interfaces= setting).
804 Currently only accepts one IP address.
805 nat_traversal
807 whether to accept/offer to support NAT (NAPT, also known as "IP
808 Masqurade") workaround for IPsec. Acceptable values are: yes and no
809 (the default). This parameter may eventually become per-connection.
810 disable_port_floating
812 whether to enable the newer NAT-T standards for port floating.
813 Acceptable values are no (the default) and yes .
814 force_keepalive
816 whether to force sending NAT-T keep-alives to support NAT which are
817 send to prevent the NAT router from closing its port when there is
818 not enough traffic on the IPsec connection. Acceptable values are:
819 yes and no (the default). This parameter may eventually become
820 per-connection.
821 keep_alive
823 The delay (in seconds) for NAT-T keep-alive packets, if these are
824 enabled using force_keepalive This parameter may eventually become
825 per-connection.
826 virtual_private
828 contains the networks that are allowed as subnet= for the remote
829 clients when using the vhost: or vnet: keywords in the subnet=
830 parameters. In other words, the address ranges that may live behind
831 a NAT router through which a client connects. This value is usually
832 set to all the RFC-1918 address space, excluding the space used in
833 the local subnet behind the NAT (An IP address cannot live at two
834 places at once). IPv4 address ranges are denoted as %v4:a.b.c.d/mm
835 and IPv6 is denoted as %v6:aaaa::bbbb:cccc:dddd:eeee/mm. One can
836 exclude subnets by using the !. For example, if the VPN server is
837 giving access to 192.168.1.0/24, this option should be set to:
838 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.
839 This parameter is only needed on the server side and not on the
840 client side that resides behind the NAT router, as the client will
841 just use its IP address for the inner IP setting. This parameter
842 may eventually become per-connection. See also leftsubnet=
843 Note: It seems that T-Mobile in the US and Rogers/Fido in Canada
845 have started using 25.0.0.0/8 as their pre-NAT range. This range
846 technically belows to the Defence Interoperable Network Services
847 Authority (DINSA), an agency of the Ministry of Defence of the
848 United Kingdom. The network range seems to not have been announced
849 for decades, which is probably why these organisasions "borrowed"
850 this range. To support roadwarriors on these 3G networks, you might
851 have to add it to the virtual_private= line.
852 oe
854 a boolean (yes/no) that determines if Opportunistic Encryption will
855 be enabled. Opportunistic Encryption is the term to describe using
856 IPsec tunnels without prearrangement. It uses IPSECKEY or TXT
857 records to announce public RSA keys for certain IP's or identities.
858 For a complete description see
860 /doc/draft-richardson-ipsec-opportunistic.txt,
861 doc/opportunism-spec.txt and doc/opportunism.howto. See also the
862 IETF BTNS working group and RFC4025.
863 The default is no.
865 This feature is only available with kernel drivers that support the
867 caching of packets (%hold eroutes or equivalent) that allows us to
868 respond to a packet from an unknown IP address. At present only the
869 (klips)mast protocol stack supports this feature.
870 nhelpers
872 how many pluto helpers are started to help with cryptographic
873 operations. Pluto will start (n-1) of them, where n is the number
874 of CPU's you have (including hypherthreaded CPU's). A value of 0
875 forces pluto to do all operations in the main process. A value of
876 -1 tells pluto to perform the above calculation. Any other value
877 forces the number to that amount.
878 crlcheckinterval
880 interval, specified in seconds, after which pluto will verify
881 loaded X.509 CRL's for expiration. If any of the CRL's is expired,
882 or if they previously failed to get updated, a new attempt at
883 updating the CRL is made. The first attempt to update a CRL is
884 started at two times the crlcheckinterval. If set to 0, which is
885 also the default value if this option is not specified, CRL
886 updating is disabled.
887 strictcrlpolicy
889 if not set, pluto is tolerant about missing or expired X.509
890 Certificate Revocation Lists (CRL's), and will allow peer
891 certificates as long as they do not appear on an expired CRL. When
892 this option is enabled, all connections with an expired or missing
893 CRL will be denied. Active connections will be terminated at rekey
894 time. This setup is more secure, but also dangerous. If the CRL is
895 fetched through an IPsec tunnel with a CRL that expired, the entire
896 VPN server will be dead in the water until a new CRL is manually
897 transferred to the machine (if it allows non-IPsec connections).
898 Acceptable values are yes or no (the default).
899 forwardcontrol
901 This option is obsolete and ignored. Please use
902 net.ipv4.ip_forward = 0 in /etc/sysctl.conf instead to control the
903 ip forwarding behaviour.
904 rp_filter
906 This option is obsolete and ignored. Please use the
907 net.ipv4.conf/[iface]/rp_filter = 0 options in /etc/sysctl.conf
908 instead. This option is badly documented; it must be 0 in many
909 cases for ipsec to function.
910 syslog
912 the syslog(2) “facility” name and priority to use for
913 startup/shutdown log messages, default daemon.error.
914 klipsdebug
916 how much KLIPS debugging output should be logged. An empty value,
917 or the magic value none, means no debugging output (the default).
918 The magic value all means full output. Otherwise only the specified
919 types of output (a quoted list, names separated by white space) are
920 enabled; for details on available debugging types, see
921 ipsec_klipsdebug(8). This KLIPS option has no effect on NETKEY,
922 Windows or BSD stacks.
923 plutodebug
925 how much Pluto debugging output should be logged. An empty value,
926 or the magic value none, means no debugging output (the default).
927 The magic value all means full output. Otherwise only the specified
928 types of output (a quoted list, names without the --debug- prefix,
929 separated by white space) are enabled; for details on available
930 debugging types, see ipsec_pluto(8).
931 uniqueids
933 whether a particular participant ID should be kept unique, with any
934 new (automatically keyed) connection using an ID from a different
935 IP address deemed to replace all old ones using that ID. Acceptable
936 values are yes (the default) and no. Participant IDs normally are
937 unique, so a new (automatically-keyed) connection using the same ID
938 is almost invariably intended to replace an old one.
939 plutorestartoncrash
941 prevent pluto from restarting after it crashed. This option should
942 only be used when debugging a crasher. It will prevent overwriting
943 a core file on a new start, or a cascade of core files. This option
944 is also required if used with plutostderrlog= to avoid clearing the
945 logs of the crasher. Values can be yes (the default) or no.
946 plutoopts
948 additional options to pass to pluto upon startup. See
949 ipsec_pluto(8).
950 plutostderrlog
952 do not use syslog, but rather log to stderr, and direct stderr to
953 the argument file.
954 pluto
956 whether to start Pluto or not; Values are yes (the default) or no
957 (useful only in special circumstances).
958 plutowait
960 should Pluto wait for each negotiation attempt that is part of
961 startup to finish before proceeding with the next? Values are yes
962 or no (the default).
963 prepluto
965 shell command to run before starting Pluto (e.g., to decrypt an
966 encrypted copy of the ipsec.secrets file). It's run in a very
967 simple way; complexities like I/O redirection are best hidden
968 within a script. Any output is redirected for logging, so running
969 interactive commands is difficult unless they use /dev/tty or
970 equivalent for their interaction. Default is none.
971 postpluto
973 shell command to run after starting Pluto (e.g., to remove a
974 decrypted copy of the ipsec.secrets file). It's run in a very
975 simple way; complexities like I/O redirection are best hidden
976 within a script. Any output is redirected for logging, so running
977 interactive commands is difficult unless they use /dev/tty or
978 equivalent for their interaction. Default is none.
979 dumpdir
981 in what directory should things started by setup (notably the Pluto
982 daemon) be allowed to dump core? The empty value (the default)
983 means they are not allowed to.
984 fragicmp
986 whether a tunnel's need to fragment a packet should be reported
987 back with an ICMP message, in an attempt to make the sender lower
988 his PMTU estimate; acceptable values are yes (the default) and no.
989 This KLIPS option has no effect on NETKEY, Windows or BSD stacks.
990 hidetos
992 whether a tunnel packet's TOS field should be set to 0 rather than
993 copied from the user packet inside; acceptable values are yes (the
994 default) and no. This KLIPS option has no effect on NETKEY, Windows
995 or BSD stacks.
996 overridemtu
998 value that the MTU of the ipsecn interface(s) should be set to,
999 overriding IPsec's (large) default. This parameter is needed only
1000 in special situations. This KLIPS option has no effect on NETKEY,
1001 Windows or BSD stacks.
1002
1004 The system automatically defines several conns to implement default
1005 policy groups. Each can be overridden by explicitly defining a new conn
1006 with the same name. If the new conn has auto=ignore, the definition is
1007 suppressed.
1008 Here are the automatically supplied definitions.
1010 conn clear
1013 type=passthrough
1014 authby=never
1015 left=%defaultroute
1016 right=%group
1017 auto=route
1018 conn clear-or-private
1020 type=passthrough
1021 left=%defaultroute
1022 leftid=%myid
1023 right=%opportunisticgroup
1024 failureshunt=passthrough
1025 keyingtries=3
1026 ikelifetime=1h
1027 salifetime=1h
1028 rekey=no
1029 auto=route
1030 conn private-or-clear
1032 type=tunnel
1033 left=%defaultroute
1034 leftid=%myid
1035 right=%opportunisticgroup
1036 failureshunt=passthrough
1037 keyingtries=3
1038 ikelifetime=1h
1039 salifetime=1h
1040 rekey=no
1041 auto=route
1042 conn private
1044 type=tunnel
1045 left=%defaultroute
1046 leftid=%myid
1047 right=%opportunisticgroup
1048 failureshunt=drop
1049 keyingtries=3
1050 ikelifetime=1h
1051 salifetime=1h
1052 rekey=no
1053 auto=route
1054 conn block
1056 type=reject
1057 authby=never
1058 left=%defaultroute
1059 right=%group
1060 auto=route
1061 # default policy
1063 conn packetdefault
1064 type=tunnel
1065 left=%defaultroute
1066 leftid=%myid
1067 left=0.0.0.0/0
1068 right=%opportunistic
1069 failureshunt=passthrough
1070 keyingtries=3
1071 ikelifetime=1h
1072 salifetime=1h
1073 rekey=no
1074 auto=route
1075 These conns are not affected by anything in conn %default. They will
1077 only work if %defaultroute works. The leftid will be the interfaces IP
1078 address; this requires that reverse DNS records be set up properly.
1079 The implicit conns are defined after all others. It is appropriate and
1081 reasonable to use also=private-or-clear (for example) in any other
1082 opportunistic conn.
1083
1085 The optional files under /etc/ipsec.d/policy, including
1086 /etc/ipsec.d/policies/clear
1089 /etc/ipsec.d/policies/clear-or-private
1090 /etc/ipsec.d/policies/private-or-clear
1091 /etc/ipsec.d/policies/private
1092 /etc/ipsec.d/policies/block
1093 may contain policy group configuration information to supplement
1096 ipsec.conf. Their contents are not security-sensitive.
1097 These files are text files. Each consists of a list of CIDR blocks, one
1099 per line. White space followed by # followed by anything to the end of
1100 the line is a comment and is ignored, as are empty lines.
1101 A connection in ipsec.conf which has right=%group or
1103 right=%opportunisticgroup is a policy group connection. When a policy
1104 group file of the same name is loaded, with
1105 ipsec auto --rereadgroups
1107 or at system start, the connection is instantiated such that each CIDR
1109 block serves as an instance's right value. The system treats the
1110 resulting instances as normal connections.
1111 For example, given a suitable connection definition private, and the
1113 file /etc/ipsec.d/policy/private with an entry 192.0.2.3, the system
1114 creates a connection instance private#192.0.2.3. This connection
1115 inherits all details from private, except that its right client is
1116 192.0.2.3.
1117
1119 The standard Openswan install includes several policy groups which
1120 provide a way of classifying possible peers into IPsec security
1121 classes: private (talk encrypted only), private-or-clear (prefer
1122 encryption), clear-or-private (respond to requests for encryption),
1123 clear and block. Implicit policy groups apply to the local host only,
1124 and are implemented by the IMPLICIT CONNECTIONS described above.
1125
1127 When choosing a connection to apply to an outbound packet caught with a
1128 %trap, the system prefers the one with the most specific eroute that
1129 includes the packet's source and destination IP addresses. Source
1130 subnets are examined before destination subnets. For initiating, only
1131 routed connections are considered. For responding, unrouted but added
1132 connections are considered.
1133 When choosing a connection to use to respond to a negotiation which
1135 doesn't match an ordinary conn, an opportunistic connection may be
1136 instantiated. Eventually, its instance will be /32 -> /32, but for
1137 earlier stages of the negotiation, there will not be enough information
1138 about the client subnets to complete the instantiation.
1139
1141 /etc/ipsec.conf
1142 /etc/ipsec.d/policies/clear
1143 /etc/ipsec.d/policies/clear-or-private
1144 /etc/ipsec.d/policies/private-or-clear
1145 /etc/ipsec.d/policies/private
1146 /etc/ipsec.d/policies/block
1147
1149 ipsec(8), ipsec_ttoaddr(8), ipsec_auto(8), ipsec_manual(8),
1150 ipsec_rsasigkey(8)
1151
1153 Designed for the FreeS/WAN project <http://www.freeswan.org> by Henry
1154 Spencer.
1155
1157 Before reporting new bugs, please ensure you are using the latest
1158 version of Openswan, and if not using KLIPS, please ensure you are
1159 using the latest kernel code for your IPsec stack.
1160 When type or failureshunt is set to drop or reject, Openswan blocks
1162 outbound packets using eroutes, but assumes inbound blocking is handled
1163 by the firewall. Openswan offers firewall hooks via an “updown” script.
1164 However, the default ipsec _updown provides no help in controlling a
1165 modern firewall.
1166 Including attributes of the keying channel (authentication methods,
1168 ikelifetime, etc.) as an attribute of a connection, rather than of a
1169 participant pair, is dubious and incurs limitations.
1170 The use of %any with the protoport= option is ambiguous. Should the SA
1172 permits any port through or should the SA negotiate any single port
1173 through? The first is a basic conn with a wildcard. The second is a
1174 template. The second is the current behaviour, and it's wrong for quite
1175 a number of uses involving TCP. The keyword %one may be introduced in
1176 the future to separate these two cases.
1177 ipsec_manual is not nearly as generous about the syntax of subnets,
1179 addresses, etc. as the usual Openswan user interfaces. Four-component
1180 dotted-decimal must be used for all addresses. It is smart enough to
1181 translate bit-count netmasks to dotted-decimal form.
1182 It would be good to have a line-continuation syntax, especially for the
1184 very long lines involved in RSA signature keys.
1185 First packet caching is only implemented for the KLIPS(NG) and MAST
1187 stacks. NETKEY returns POSIX-breaking responses, visiable as connect:
1188 Resource temporarily unavailable errors. This affects Opportunistic
1189 Encryption and DPD. Functionality on the BSD and Windows stacks is
1190 unknown.
1191 Some state information is only available when using KLIPS, and will
1193 return errors on other IPsec stacks. These include ipsec eroute, ipsec
1194 spi and ipsec look.
1195 Multiple L2TP clients behind the same NAT router, and multiple L2TP
1197 clients behind different NAT routers using the same Virtual IP is
1198 currently only working for the KLIPSNG stack.
1199 The ability to specify different identities, authby, and public keys
1201 for different automatic-keyed connections between the same participants
1202 is misleading; this doesn't work dependably because the identity of the
1203 participants is not known early enough. This is especially awkward for
1204 the “Road Warrior” case, where the remote IP address is specified as
1205 0.0.0.0, and that is considered to be the “participant” for such
1206 connections.
1207 In principle it might be necessary to control MTU on an
1209 interface-by-interface basis, rather than with the single global
1210 override that overridemtu provides. This feature is planned for a
1211 future release.
1212 A number of features which could be implemented in both manual and
1214 automatic keying actually are not yet implemented for manual keying.
1215 This is unlikely to be fixed any time soon.
1216 If conns are to be added before DNS is available, left=FQDN,
1218 leftnextop=FQDN, and leftrsasigkey=%dnsonload will fail.
1219 ipsec_pluto(8) does not actually use the public key for our side of a
1220 conn but it isn't generally known at a add-time which side is ours
1221 (Road Warrior and Opportunistic conns are currently exceptions).
1222 The myid option does not affect explicit
1224 ipsec auto --add or ipsec auto --replace commands for implicit conns.
1225[FIXME: source] 10/29/2011 IPSEC.CONF(5)