1IPSEC.CONF(5) 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
20 space followed by # followed by anything to the end of the line is a
21 comment and is ignored, as are empty lines which are not within a sec‐
22 tion.
23 A line which contains include and a file name, separated by white
26 space, is replaced by the contents of that file, preceded and followed
27 by empty lines. If the file name is not a full pathname, it is consid‐
28 ered to be relative to the directory containing the including file.
29 Such inclusions can be nested. Only a single filename may be supplied,
30 and it may not contain white space, but it may include shell wildcards
31 (see sh(1)); for example:
32 include ipsec.*.conf
35 The intention of the include facility is mostly to permit keeping
38 information on connections, or sets of connections, separate from the
39 main configuration file. This permits such connection descriptions to
40 be changed, copied to the other security gateways involved, etc., with‐
41 out having to constantly extract them from the configuration file and
42 then insert them back into it. Note also the also and alsoflip parame‐
43 ters (described below) which permit splitting a single logical section
44 (e.g. a connection description) into several actual sections.
45 The first significant line of the file must specify the version of this
48 specification that it conforms to:
49 version 2
52 A section begins with a line of the form:
55 type name
58 where type indicates what type of section follows, and name is an arbi‐
61 trary name which distinguishes the section from others of the same
62 type. (Names must start with a letter and may contain only letters,
63 digits, periods, underscores, and hyphens.) All subsequent non-empty
64 lines which begin with white space are part of the section; comments
65 within a section must begin with white space too. There may be only one
66 section of a given type with a given name.
67 Lines within the section are generally of the form
70 parameter=value
73 (note the mandatory preceding white space). There can be white space on
76 either side of the =. Parameter names follow the same syntax as section
77 names, and are specific to a section type. Unless otherwise explicitly
78 specified, no parameter name may appear more than once in a section.
79 An empty value stands for the system default value (if any) of the
82 parameter, i.e. it is roughly equivalent to omitting the parameter line
83 entirely. A value may contain white space only if the entire value is
84 enclosed in double quotes ("); a value cannot itself contain a double
85 quote, nor may it be continued across more than one line.
86 Numeric values are specified to be either an “integer” (a sequence of
89 digits) or a “decimal number” (sequence of digits optionally followed
90 by `.' and another sequence of digits).
91 There is currently one parameter which is available in any type of sec‐
94 tion:
95 also the value is a section name; the parameters of that section are
98 appended to this section, as if they had been written as part of
99 it. The specified section must exist, must follow the current
100 one, and must have the same section type. (Nesting is permitted,
101 and there may be more than one also in a single section,
102 although it is forbidden to append the same section more than
103 once.) This allows, for example, keeping the encryption keys for
104 a connection in a separate file from the rest of the descrip‐
105 tion, by using both an also parameter and an include line. (Cau‐
106 tion, see BUGS below for some restrictions.)
107 alsoflip
110 can be used in a conn section. It acts like an also that flips
111 the referenced section's entries left-for-right.
112 Parameter names beginning with x- (or X-, or x_, or X_) are reserved
115 for user extensions and will never be assigned meanings by IPsec.
116 Parameters with such names must still observe the syntax rules (limits
117 on characters used in the name; no white space in a non-quoted value;
118 no newlines or double quotes within the value). All other as-yet-unused
119 parameter names are reserved for future IPsec improvements.
120 A section with name %default specifies defaults for sections of the
123 same type. For each parameter in it, any section of that type which
124 does not have a parameter of the same name gets a copy of the one from
125 the %default section. There may be multiple %default sections of a
126 given type, but only one default may be supplied for any specific
127 parameter name, and all %default sections of a given type must precede
128 all non-%default sections of that type. %default sections may not con‐
129 tain also or alsoflip parameters.
130 Currently there are two types of section: a config section specifies
133 general configuration information for IPsec, while a conn section spec‐
134 ifies an IPsec connection.
135
138 A conn section contains a connection specification, defining a network
139 connection to be made using IPsec. The name given is arbitrary, and is
140 used to identify the connection to ipsec_auto(8) and ipsec_manual(8).
141 Here's a simple example:
142 conn snt
146 left=10.11.11.1
147 leftsubnet=10.0.1.0/24
148 leftnexthop=172.16.55.66
149 leftsourceip=10.0.1.1
150 right=192.168.22.1
151 rightsubnet=10.0.2.0/24
152 rightnexthop=172.16.88.99
153 rightsourceip=10.0.2.1
154 keyingtries=%forever
155 A note on terminology... In automatic keying, there are two kinds of
159 communications going on: transmission of user IP packets, and gate‐
160 way-to-gateway negotiations for keying, rekeying, and general control.
161 The data path (a set of “IPsec SAs”) used for user packets is herein
162 referred to as the “connection”; the path used for negotiations (built
163 with “ISAKMP SAs”) is referred to as the “keying channel”.
164 To avoid trivial editing of the configuration file to suit it to each
167 system involved in a connection, connection specifications are written
168 in terms of left and right participants, rather than in terms of local
169 and remote. Which participant is considered left or right is arbitrary;
170 IPsec figures out which one it is being run on based on internal infor‐
171 mation. This permits using identical connection specifications on both
172 ends. There are cases where there is no symmetry; a good convention is
173 to use left for the local side and right for the remote side (the first
174 letters are a good mnemonic).
175 Many of the parameters relate to one participant or the other; only the
178 ones for left are listed here, but every parameter whose name begins
179 with left has a right counterpart, whose description is the same but
180 with left and right reversed.
181 Parameters are optional unless marked “(required)”; a parameter
184 required for manual keying need not be included for a connection which
185 will use only automatic keying, and vice versa.
186 CONN PARAMETERS: GENERAL
189 The following parameters are relevant to both automatic and manual key‐
190 ing. Unless otherwise noted, for a connection to work, in general it is
191 necessary for the two ends to agree exactly on the values of these
192 parameters.
193 type the type of the connection; currently the accepted values are
196 tunnel (the default) signifying a host-to-host, host-to-subnet,
197 or subnet-to-subnet tunnel; transport, signifying host-to-host
198 transport mode; passthrough, signifying that no IPsec processing
199 should be done at all; drop, signifying that packets should be
200 discarded; and reject, signifying that packets should be dis‐
201 carded and a diagnostic ICMP returned.
202 left (required) the IP address of the left participant's public-net‐
205 work interface, in any form accepted by ipsec_ttoaddr(3) or one
206 of several magic values. If it is %defaultroute, and the config
207 setup section's, interfaces specification contains %default‐
208 route, left will be filled in automatically with the local
209 address of the default-route interface (as determined at IPsec
210 startup time); this also overrides any value supplied for left‐
211 nexthop. (Either left or right may be %defaultroute, but not
212 both.) The value %any signifies an address to be filled in (by
213 automatic keying) during negotiation. The value %opportunistic
214 signifies that both left and leftnexthop are to be filled in (by
215 automatic keying) from DNS data for left's client. The values
216 %group and %opportunisticgroup makes this a policy group conn:
217 one that will be instantiated into a regular or opportunistic
218 conn for each CIDR block listed in the policy group file with
219 the same name as the conn.
220 leftsubnet
223 private subnet behind the left participant, expressed as net‐
224 work/netmask (actually, any form acceptable to ipsec_ttosub‐
225 net(3)); if omitted, essentially assumed to be left/32, signify‐
226 ing that the left end of the connection goes to the left partic‐
227 ipant only. If the global option virtual_private has been set,
228 the special keyword vhost:%priv can be used to designate the
229 allowed NAT'ed networks this option can take. If one wants to
230 support both the allowed virtual_private networks as well as
231 non-NAT'ed connection, this subnet option can be set to right‐
232 subnet=vhost:%priv, %no. The special value %priv will be filled
233 in with the network ranges specified in the global option vir‐
234 tual_private=
235 leftprotoport
238 allowed protocols and ports over connection, also called Port
239 Selectors. The argument is in the form protocol, which can be a
240 number or a name that will be looked up in /etc/protocols, such
241 as leftprotoport=icmp, or in the form of protocol/port, such as
242 tcp/smtp. Ports can be defined as a number (eg. 25) or as a name
243 (eg smtp) which will be looked up in /etc/services. A special
244 keyword %any can be used to allow all ports of a certain proto‐
245 col. The most common use of this option is for L2TP connections
246 to only allow l2tp packets (UDP port 1701), eg: leftproto‐
247 port=17/1701. Some clients, notably older Windows XP and some
248 Mac OSX clients, use a random high port as source port. In those
249 cases rightprotoport=17/%any can be used to allow all UDP traf‐
250 fic on the connection. Note that this option is part of the pro‐
251 posal, so it cannot be arbitrarily left out if one end does not
252 care about the traffic selection over this connection - both
253 peers have to agree. The Port Selectors show up in the output of
254 ipsec eroute and ipsec auto --status eg:"l2tp":
255 193.110.157.131[@aivd.xelernace.com]:7/1701...%any:17/1701 This
256 option only filters outbound traffic. Inbound traffic selection
257 must still be based on firewall rules activated by an updown
258 script. The variablees $PLUTO_MY_PROTOCOL, $PLUTO_PEER_PROTOCOL,
259 $PLUTO_MY_PORT, and $PLUTO_PEER_PORT are available for use in
260 updown scripts. Older workarounds for bugs involved a setting of
261 17/0 to denote all ports were allowed. This notation should no
262 longer be used.
263 leftnexthop
266 next-hop gateway IP address for the left participant's connec‐
267 tion to the public network; defaults to %direct (meaning right).
268 If the value is to be overridden by the left=%defaultroute
269 method (see above), an explicit value must not be given. If that
270 method is not being used, but leftnexthop is %defaultroute, and
271 interfaces=%defaultroute is used in the config setup section,
272 the next-hop gateway address of the default-route interface will
273 be used. The magic value %direct signifies a value to be filled
274 in (by automatic keying) with the peer's address. Relevant only
275 locally, other end need not agree on it.
276 leftsourceip
279 the IP address for this host to use when transmitting a packet
280 to the other side of this link. Relevant only locally, the other
281 end need not agree. This option is used to make the gateway
282 itself use its internal IP, which is part of the leftsubnet, to
283 communicate to the rightsubnet or right. Otherwise, it will use
284 its nearest IP address, which is its public IP address. This
285 option is mostly used when defining subnet-subnet connections,
286 so that the gateways can talk to each other and the subnet at
287 the other end, without the need to build additional host-subnet,
288 subnet-host and host-host tunnels.
289 leftupdown
292 what “updown” script to run to adjust routing and/or firewalling
293 when the status of the connection changes (default ipsec
294 _updown). May include positional parameters separated by white
295 space (although this requires enclosing the whole string in
296 quotes); including shell metacharacters is unwise. See
297 ipsec_pluto(8) for details. Relevant only locally, other end
298 need not agree on it.
299 leftfirewall
302 This option is obsolete and should not used anymore.
303 CONN PARAMETERS: AUTOMATIC KEYING
306 The following parameters are relevant for automatic keying, the normal
307 mode of operation for IPsec. They are ignored in manual keying. Unless
308 otherwise noted, for a connection to work, in general it is necessary
309 for the two ends to agree exactly on the values of these parameters.
310 keyexchange
313 method of key exchange; the default and currently the only
314 accepted value is ike
315 auto what operation, if any, should be done automatically at IPsec
318 startup; currently-accepted values are add (signifying an ipsec
319 auto --add), route (signifying that plus an ipsec auto
320 --route), start (signifying that plus an ipsec auto --up), man‐
321 ual (signifying an ipsec manual --up), and ignore (also the
322 default) (signifying no automatic startup operation). See the
323 config setup discussion below. Relevant only locally, other end
324 need not agree on it (but in general, for an intended-to-be-per‐
325 manent connection, both ends should use auto=start to ensure
326 that any reboot causes immediate renegotiation). For roadwarrior
327 connections (right=%any), it is not known where the client will
328 show up, so one has to use auto=add
329 auth whether authentication should be done as part of ESP encryption,
332 or separately using the AH protocol; acceptable values are esp
333 (the default) and ah.
334 authby how the two security gateways should authenticate each other;
337 acceptable values are secret for shared secrets, rsasig for RSA
338 digital signatures (the default), secret|rsasig for either, and
339 never if negotiation is never to be attempted or accepted (use‐
340 ful for shunt-only conns). Digital signatures are superior in
341 every way to shared secrets.
342 ike IKE encryption/authentication algorithm to be used for the con‐
345 nection (phase 1 aka ISAKMP SA). The format is
346 "cipher-hash;modpgroup, cipher-hash;modpgroup, ..." Any left out
347 option will be filled in with all allowed default options. Mul‐
348 tiple proposals are seperated by a comma. If an ike= line is
349 specified, no other received proposals will be accepted. For‐
350 merly there was a distinction (by using a "!" symbol) between
351 "strict mode" or not. That mode has been obsoleted. If an ike=
352 option is specified, the mode is always strict, meaning no other
353 received proposals will be accepted. Some examples are
354 ike=3des-sha1,aes-sha1, ike=aes, ike=aes128-md5;modp2048,
355 ike=3des-md5;modp1024,esp=aes-sha1;modp1536 or ike=modp1536. The
356 options must be suitable as a value of ipsec_spi(8)'s --ike
357 option. The default is to use IKE, and to allow all combinations
358 of:
359 cipher: 3des or aes
361 hash: sha1 or md5
362 pfsgroup (DHgroup): modp1024 or modp1536
363 If Openswan was compiled with extra INSECURE and BROKEN options,
366 then the des (1des) and null cipher, as well as modp768 are
367 available. This turns your VPN into a joke. Do not enable these
368 options.
369 esp ESP encryption/authentication algorithm to be used for the con‐
372 nection (phase2 aka IPsec SA). The format is identical to the
373 ike option listed above. The options must be suitable as a value
374 of ipsec_spi(8)'s --esp option. The default is to use ESP. The
375 default values are the same as for ike= Note also that not all
376 ciphers available to the kernel (eg through CryptoAPI) are nec‐
377 essarilly supported here.
378 ah AH authentication algorithm to be used for the connection, e.g
381 here. hmac-md5 The options must be suitable as a value of
382 ipsec_spi(8)'s --ah option. The default is not to use AH. If for
383 some (invalid) reason you still think you need AH, please use
384 esp with the null encryption cipher instead. Note also that not
385 all ciphers available to the kernel (eg through CryptoAPI) are
386 necessarilly supported here.
387 leftid how the left participant should be identified for authentica‐
390 tion; defaults to left. Can be an IP address (in any
391 ipsec_ttoaddr(3) syntax) or a fully-qualified domain name pre‐
392 ceded by @ (which is used as a literal string and not resolved).
393 The magic value %myid stands for the current setting of myid.
394 leftrsasigkey
397 the left participant's public key for RSA signature authentica‐
398 tion, in RFC 2537 format using ipsec_ttodata(3) encoding. The
399 magic value %none means the same as not specifying a value (use‐
400 ful to override a default). The value %dnsondemand (the default)
401 means the key is to be fetched from DNS at the time it is
402 needed. The value %dnsonload means the key is to be fetched from
403 DNS at the time the connection description is read from
404 ipsec.conf; currently this will be treated as %none if
405 right=%any or right=%opportunistic. The value %dns is currently
406 treated as %dnsonload but will change to %dnsondemand in the
407 future. The identity used for the left participant must be a
408 specific host, not %any or another magic value. The value %cert
409 will load the information required from a certificate defined in
410 %leftcert and automatically define leftid for you. Caution: if
411 two connection descriptions specify different public keys for
412 the same leftid, confusion and madness will ensue.
413 leftrsasigkey2
416 if present, a second public key. Either key can authenticate the
417 signature, allowing for key rollover.
418 leftcert
421 If you are using leftrsasigkey=%cert this defines the certifi‐
422 cate you would like to use. It should point to a X.509 encoded
423 certificate file. If you do not specify a full pathname, by
424 default it will look in /etc/ipsec.d/certs. If openswan has been
425 compiled with USE_SMARTCARD=true, then this option can also be
426 set to leftcert=%smartcard. If multiple smartcards or USB tokens
427 are present, they can be specified using leftcert=%smart‐
428 card<reader nr><PKCS#15 key id>
429 leftsendcert
432 This option configures when Openswan will send X.509 certifi‐
433 cates to the remote host. Acceptable values are yes|always (sig‐
434 nifying that we should always send a certificate), ifasked (sig‐
435 nifying that we should send a certificate if the remote end asks
436 for it), and no|never (signifying that we will never send a
437 X.509 certificate). The default for this option is ifasked which
438 may break compatibility with other vendor's IPSec implementa‐
439 tions, such as Cisco and SafeNet. If you find that you are get‐
440 ting errors about no ID/Key found, you likely need to set this
441 to always. This per-conn option replaces the obsolete global
442 nocrsend option.
443 leftca specifies the authorized Certificate Agency (CA) that signed the
446 certificate of the peer. If undefined, it defaults to the CA
447 that signed the certificate specified in leftcert. The special
448 rightca=%same is implied when not specifying a rightca and means
449 that only peers with certificates signed by the same CA as the
450 leftca will be allowed. This option is only useful in complex
451 multi CA certificate situations. When using a single CA, it can
452 be safely omitted for left and right.
453 leftxauthserver
456 Left is an XAUTH server. This can use PAM for authentication or
457 md5 passwords in /etc/ipsec.d/passwd. These are additional cre‐
458 dentials to verify the user identity, and should not be confused
459 with the XAUTH group secret, which is just a regular PSK defined
460 in ipsec.secrets. The other side of the connection should be
461 configured as rightxauthclient. XAUTH connections cannot rekey,
462 so rekey=no should be specified in this conn. For further
463 details on how to compile and use XAUTH, see README.XAUTH.
464 Acceptable values are yes or no (the default).
465 leftxauthclient
468 Left is an XAUTH client. The xauth connection will have to be
469 started interactively and cannot be configured using auto=start.
470 Instead, it has to be started from the commandline using ipsec
471 auto --up connname. You will then be prompted for the username
472 and password. To setup an XAUTH connection non-interactively,
473 which defeats the whole purpose of XAUTH, but is regularly
474 requested by users, it is possible to use a whack command -
475 ipsec whack --name baduser --ipsecgroup-xauth --xauthname
476 badusername --xauthpass password --initiate The other side of
477 the connection should be configured as rightxauthserver. Accept‐
478 able values are yes or no (the default).
479 leftmodecfgserver
482 Left is a Mode Config server. It can push network configuration
483 to the client. Acceptable values are yes or no (the default).
484 leftmodecfgclient
487 Left is a Mode Config client. It can receive network configura‐
488 tion from the server. Acceptable values are yes or no (the
489 default).
490 forceencaps
493 In some cases, for example when ESP packets are filtered or when
494 a broken IPsec peer does not properly recognise NAT, it can be
495 useful to force RFC-3948 encapsulation. forceencaps=yes forces
496 the NAT detection code to lie and tell the remote peer that
497 RFC-3948 encapsulation (ESP in UDP port 4500 packets) is
498 required. For this option to have any effect, the setup section
499 option nat_traversal=yes needs to be set. Acceptable values are
500 yes or no (the default).
501 dpddelay
504 Set the delay (in seconds) between Dead Peer Dectection (RFC
505 3706) keepalives (R_U_THERE, R_U_THERE_ACK) that are sent for
506 this connection (default 30 seconds). If dpdtimeout is set, but
507 not dpddelay, dpddelay will be set to the default.
508 dpdtimeout
511 Set the length of time (in seconds) we will idle without hearing
512 either an R_U_THERE poll from our peer, or an R_U_THERE_ACK
513 reply. After this period has elapsed with no response and no
514 traffic, we will declare the peer dead, and remove the SA
515 (default 120 seconds). If dpddelay is set, but not dpdtimeout,
516 dpdtimeout will be set to the default.
517 dpdaction
520 When a DPD enabled peer is declared dead, what action should be
521 taken. hold (default) means the eroute will be put into %hold
522 status, while clear means the eroute and SA with both be
523 cleared. dpdaction=clear is really only usefull on the server of
524 a Road Warrior config. The action restart is used on tunnels
525 that need to be permanently up, and have static IP addresses.
526 modecfgpull
529 Pull the Mode Config network information from the server.
530 Acceptable values are yes or no (the default).
531 pfs whether Perfect Forward Secrecy of keys is desired on the con‐
534 nection's keying channel (with PFS, penetration of the
535 key-exchange protocol does not compromise keys negotiated ear‐
536 lier); Since there is no reason to ever refuse PFS, Openswan
537 will allow a connection defined with pfs=no to use PFS anyway.
538 Acceptable values are yes (the default) and no.
539 pfsgroup
542 PFS group to be used if pfs=yes, e.g. pfsgroup=modp1536 Because
543 PFS group is not negotiated it is single valued and must be pre‐
544 viously coordinated with peer. Possible values are: modp1024,
545 modp1536, modp2048, modp3072 and modp4096. If not specified, it
546 will use same DH group of phase1. Default value is the same
547 value as Phase1's DH group.
548 aggrmode
551 Use Aggressive Mode instead of Main Mode. Aggressive Mode is
552 less secure, and vulnerable to Denial Of Service attacks. It is
553 also vulnerable to brute force attacks with software such as
554 ikecrack. It should not be used, and it should especially not be
555 used with XAUTH and group secrets (PSK). If the remote system
556 administrator insists on staying irresponsible, enable this
557 option.
558 Aggressive Mode is further limited to only one proposal - there
560 is no room for negotation. Therefor it is mandatory for Aggres‐
561 sive Mode connections that both ike= and esp= options are speci‐
562 fied with exactly one fully specified proposal. Acceptable val‐
563 ues are yes or no (the default).
564 keylife
567 how long a particular instance of a connection (a set of encryp‐
568 tion/authentication keys for user packets) should last, from
569 successful negotiation to expiry; acceptable values are an inte‐
570 ger optionally followed by s (a time in seconds) or a decimal
571 number followed by m, h, or d (a time in minutes, hours, or days
572 respectively) (default 8h, maximum 24h). Normally, the connec‐
573 tion is renegotiated (via the keying channel) before it expires.
574 The two ends need not exactly agree on keylife, although if they
575 do not, there will be some clutter of superseded connections on
576 the end which thinks the lifetime is longer.
577 rekey whether a connection should be renegotiated when it is about to
580 expire; acceptable values are yes (the default) and no. The two
581 ends need not agree, but while a value of no prevents Pluto from
582 requesting renegotiation, it does not prevent responding to
583 renegotiation requested from the other end, so no will be
584 largely ineffective unless both ends agree on it.
585 rekeymargin
588 how long before connection expiry or keying-channel expiry
589 should attempts to negotiate a replacement begin; acceptable
590 values as for keylife (default 9m). Relevant only locally, other
591 end need not agree on it.
592 rekeyfuzz
595 maximum percentage by which rekeymargin should be randomly
596 increased to randomize rekeying intervals (important for hosts
597 with many connections); acceptable values are an integer, which
598 may exceed 100, followed by a `%' (default set by
599 ipsec_pluto(8), currently 100%). The value of rekeymargin, after
600 this random increase, must not exceed keylife. The value 0% will
601 suppress time randomization. Relevant only locally, other end
602 need not agree on it.
603 keyingtries
606 how many attempts (a whole number or %forever) should be made to
607 negotiate a connection, or a replacement for one, before giving
608 up (default %forever). The value %forever means “never give up”
609 (obsolete: this can be written 0). Relevant only locally, other
610 end need not agree on it.
611 ikelifetime
614 how long the keying channel of a connection (buzzphrase: “ISAKMP
615 SA”) should last before being renegotiated; acceptable values as
616 for keylife (default set by ipsec_pluto(8), currently 1h, maxi‐
617 mum 24h). The two-ends-disagree case is similar to that of
618 keylife.
619 compress
622 whether IPComp compression of content is proposed on the connec‐
623 tion (link-level compression does not work on encrypted data, so
624 to be effective, compression must be done before encryption);
625 acceptable values are yes and no (the default). The two ends
626 need not agree. A value of yes causes IPsec to propose both com‐
627 pressed and uncompressed, and prefer compressed. A value of no
628 prevents IPsec from proposing compression; a proposal to com‐
629 press will still be accepted.
630 disablearrivalcheck
633 whether KLIPS's normal tunnel-exit check (that a packet emerging
634 from a tunnel has plausible addresses in its header) should be
635 disabled; acceptable values are yes and no (the default). Tun‐
636 nel-exit checks improve security and do not break any normal
637 configuration. Relevant only locally, other end need not agree
638 on it.
639 failureshunt
642 what to do with packets when negotiation fails. The default is
643 none: no shunt; passthrough, drop, and reject have the obvious
644 meanings.
645 CONN PARAMETERS: MANUAL KEYING
648 The following parameters are relevant only to manual keying, and are
649 ignored in automatic keying. It is EXTREMELY UNLIKELY that you will
650 actually want to use manual keying. It is much harder to configure then
651 automatic keying, and inheritently insecure when used for a prolonged
652 time (eg production) due to the complete lack of key renewal, session
653 keys or perfect forward secrecy.
654 Unless otherwise noted, for a connection to work, in general it is nec‐
657 essary for the two ends to agree exactly on the values of these parame‐
658 ters. A manually-keyed connection must specify at least one of AH or
659 ESP.
660 spi (this or spibase required for manual keying) the SPI number to
663 be used for the connection (see ipsec_manual(8)); must be of the
664 form 0xhex, where hex is one or more hexadecimal digits (note,
665 it will generally be necessary to make spi at least 0x100 to be
666 acceptable to KLIPS, and use of SPIs in the range 0x100-0xfff is
667 recommended)
668 spibase
671 (this or spi required for manual keying) the base number for the
672 SPIs to be used for the connection (see ipsec_manual(8)); must
673 be of the form 0xhex0, where hex is one or more hexadecimal dig‐
674 its (note, it will generally be necessary to make spibase at
675 least 0x100 for the resulting SPIs to be acceptable to KLIPS,
676 and use of numbers in the range 0x100-0xff0 is recommended)
677 espenckey
680 ESP encryption key (must be suitable as a value of
681 ipsec_spi(8)'s --enckey option) (may be specified separately for
682 each direction using leftespenckey (leftward SA) and righte‐
683 spenckey parameters)
684 espauthkey
687 ESP authentication key (must be suitable as a value of
688 ipsec_spi(8)'s --authkey option) (may be specified separately
689 for each direction using leftespauthkey (leftward SA) and right‐
690 espauthkey parameters)
691 espreplay_window
694 ESP replay-window setting, an integer from 0 (the ipsec_manual
695 default, which turns off replay protection) to 64; relevant only
696 if ESP authentication is being used
697 leftespspi
700 SPI to be used for the leftward ESP SA, overriding automatic
701 assignment using spi or spibase; typically a hexadecimal number
702 beginning with 0x
703 ahkey (required if ah is present) AH authentication key (must be suit‐
706 able as a value of ipsec_spi(8)'s --authkey option) (may be
707 specified separately for each direction using leftahkey (left‐
708 ward SA) and rightahkey parameters)
709 ahreplay_window
712 AH replay-window setting, an integer from 0 (the ipsec_manual
713 default, which turns off replay protection) to 64
714 leftahspi
717 SPI to be used for the leftward AH SA, overriding automatic
718 assignment using spi or spibase; typically a hexadecimal number
719 beginning with 0x
720
723 At present, the only config section known to the IPsec software is the
724 one named setup, which contains information used when the software is
725 being started (see ipsec_setup(8)). Here's an example:
726 config setup
730 interfaces="ipsec0=eth1 ipsec1=ppp0"
731 klipsdebug=none
732 plutodebug=control
733 nat_traversal=yes
734 virtual_private=%v4:10.0.0.0/8,%v4:192.168.0.0/16,%4:172.16.0.0/12
735 Parameters are optional unless marked “(required)”.
739 The currently-accepted parameter names in a config setup section are:
742 myid the identity to be used for %myid. %myid is used in the implicit
745 policy group conns and can be used as an identity in explicit
746 conns. If unspecified, %myid is set to the IP address in
747 %defaultroute (if that is supported by a TXT record in its
748 reverse domain), or otherwise the system's hostname (if that is
749 supported by a TXT record in its forward domain), or otherwise
750 it is undefined. An explicit value generally starts with ``@''.
751 interfaces
754 This option is for KLIPS and KLIPSNG (mast) only and will be
755 ignored when using NETKEY, Windows or BSD stacks. It specifies
756 the virtual and physical interfaces for IPsec to use: a single
757 virtual=physical pair, a (quoted!) list of pairs separated by
758 white space, or %none. One of the pairs may be written as
759 %defaultroute, which means: find the interface d that the
760 default route points to, and then act as if the value was
761 ``ipsec0=d''. %defaultroute is the default; %none must be used
762 to denote no interfaces. If %defaultroute is used (implicitly or
763 explicitly) information about the default route and its inter‐
764 face is noted for use by ipsec_manual(8) and ipsec_auto(8).)
765 nat_traversal
768 whether to accept/offer to support NAT (NAPT, also known as "IP
769 Masqurade") workaround for IPsec. Acceptable values are: yes and
770 no (the default). This parameter may eventually become per-con‐
771 nection.
772 virtual_private
775 contains the networks that are allowed as subnet= for the remote
776 client. In other words, the address ranges that may live behind
777 a NAT router through which a client connects. This value is usu‐
778 ally set to all the RFC-1918 address space, excluding the space
779 used in the local subnet behind the NAT (An IP address cannot
780 live at two places at once). IPv4 address ranges are denoted as
781 %v4:a.b.c.d/mm and IPv6 is denoted as
782 %v6:aaaa::bbbb:cccc:dddd/mm. One can exclude subnets by using
783 the !. For example, if the VPN server is giving access to
784 192.168.1.0/24, this option should be set to: virtual_pri‐
785 vate=%v4:10.0.0.0/8,%v4:192.168.0.0/16,%4:172.16.0.0/12,%v4:!192.168.1.0/24.
786 This parameter is only needed on the server side and not on the
787 client side that resides behind the NAT router, as the client
788 will just use its IP address for the inner IP setting. This
789 parameter may eventually become per-connection.
790 nhelpers
793 how many pluto helpers are started to help with cryptographic
794 operations. Pluto will start (n-1) of them, where n is the num‐
795 ber of CPU's you have (including hypherthreaded CPU's). A value
796 of 0 forces pluto to do all operations in the main process. A
797 value of -1 tells pluto to perform the above calculation. Any
798 other value forces the number to that amount.
799 myid the identity to be used for %myid. %myid is used in the implicit
802 policy group conns and can be used as an identity in explicit
803 conns. If unspecified, %myid is set to the IP address in
804 %defaultroute (if that is supported by a TXT record in its
805 reverse domain), or otherwise the system's hostname (if that is
806 supported by a TXT record in its forward domain), or otherwise
807 it is undefined. An explicit value generally starts with ``@''.
808 crlcheckinterval
811 interval, specified in seconds, after which pluto will verify
812 loaded X.509 CRL's for expiration. If any of the CRL's is
813 expired, or if they previously failed to get updated, a new
814 attempt at updating the CRL is made. The first attempt to update
815 a CRL is started at two times the crlcheckinterval. If set to 0,
816 which is also the default value if this option is not specified,
817 CRL updating is disabled.
818 strictcrlpolicy
821 if not set, pluto is tolerant about missing or expired X.509
822 Certificate Revocation Lists (CRL's), and will allow peer cer‐
823 tificates as long as they do not appear on an expired CRL. When
824 this option is enabled, all connections with an expired or miss‐
825 ing CRL will be denied. Active connections will be terminated at
826 rekey time. This setup is more secure, but also dangerous. If
827 the CRL is fetched through an IPsec tunnel with a CRL that
828 expired, the entire VPN server will be dead in the water until a
829 new CRL is manually transferred to the machine (if it allows
830 non-IPsec connections). Acceptable values are yes or no (the
831 default).
832 forwardcontrol
835 whether setup should turn IP forwarding on (if it's not already
836 on) as IPsec is started, and turn it off again (if it was off)
837 as IPsec is stopped; acceptable values are yes and (the default)
838 no. For this to have full effect, forwarding must be disabled
839 before the hardware interfaces are brought up (e.g.,
840 net.ipv4.ip_forward = 0 in /etc/sysctl.conf), because IPsec
841 doesn't get control early enough to do that. If this option is
842 not specified, and subnet-subnet tunnels are configured, then IP
843 forwarding should be enabled by the system administrator.
844 rp_filter
847 whether and how setup should adjust the reverse path filtering
848 mechanism for the physical devices to be used. Values are
849 %unchanged (to leave it alone) or 0, 1, 2 (values to set it to).
850 /proc/sys/net/ipv4/conf/PHYS/rp_filter is badly documented; it
851 must be 0 in many cases for ipsec to function. The default value
852 for the parameter is 0, that is, to disable rp_filter for all
853 interfaces used.
854 syslog the syslog(2) “facility” name and priority to use for
857 startup/shutdown log messages, default daemon.error.
858 klipsdebug
861 how much KLIPS debugging output should be logged. An empty
862 value, or the magic value none, means no debugging output (the
863 default). The magic value all means full output. Otherwise only
864 the specified types of output (a quoted list, names separated by
865 white space) are enabled; for details on available debugging
866 types, see ipsec_klipsdebug(8). This KLIPS option has no effect
867 on NETKEY, Windows or BSD stacks.
868 plutodebug
871 how much Pluto debugging output should be logged. An empty
872 value, or the magic value none, means no debugging output (the
873 default). The magic value all means full output. Otherwise only
874 the specified types of output (a quoted list, names without the
875 --debug- prefix, separated by white space) are enabled; for
876 details on available debugging types, see ipsec_pluto(8).
877 plutorestartoncrash
880 prevent pluto from restarting after it crashed. This option
881 should only be used when a post-mortem of a core file is
882 desired. It prevents pluto from restarting and possibly over‐
883 writing an older core file.
884 plutoopts
887 additional options to pass to pluto upon startup. See
888 ipsec_pluto(8).
889 plutostderrlog
892 do not use syslog, but rather log to stderr, and direct stderr
893 to the argument file.
894 dumpdir
897 in what directory should things started by setup (notably the
898 Pluto daemon) be allowed to dump core? The empty value (the
899 default) means they are not allowed to.
900 manualstart
903 which manually-keyed connections to set up at startup (empty, a
904 name, or a quoted list of names separated by white space); see
905 ipsec_manual(8). Default is none.
906 pluto whether to start Pluto or not; Values are yes (the default) or
909 no (useful only in special circumstances).
910 plutowait
913 should Pluto wait for each negotiation attempt that is part of
914 startup to finish before proceeding with the next? Values are
915 yes or no (the default).
916 prepluto
919 shell command to run before starting Pluto (e.g., to decrypt an
920 encrypted copy of the ipsec.secrets file). It's run in a very
921 simple way; complexities like I/O redirection are best hidden
922 within a script. Any output is redirected for logging, so run‐
923 ning interactive commands is difficult unless they use /dev/tty
924 or equivalent for their interaction. Default is none.
925 postpluto
928 shell command to run after starting Pluto (e.g., to remove a
929 decrypted copy of the ipsec.secrets file). It's run in a very
930 simple way; complexities like I/O redirection are best hidden
931 within a script. Any output is redirected for logging, so run‐
932 ning interactive commands is difficult unless they use /dev/tty
933 or equivalent for their interaction. Default is none.
934 fragicmp
937 whether a tunnel's need to fragment a packet should be reported
938 back with an ICMP message, in an attempt to make the sender
939 lower his PMTU estimate; acceptable values are yes (the default)
940 and no. This KLIPS option has no effect on NETKEY, Windows or
941 BSD stacks.
942 hidetos
945 whether a tunnel packet's TOS field should be set to 0 rather
946 than copied from the user packet inside; acceptable values are
947 yes (the default) and no. This KLIPS option has no effect on
948 NETKEY, Windows or BSD stacks.
949 uniqueids
952 whether a particular participant ID should be kept unique, with
953 any new (automatically keyed) connection using an ID from a dif‐
954 ferent IP address deemed to replace all old ones using that ID.
955 Acceptable values are yes (the default) and no. Participant IDs
956 normally are unique, so a new (automatically-keyed) connection
957 using the same ID is almost invariably intended to replace an
958 old one.
959 overridemtu
962 value that the MTU of the ipsecn interface(s) should be set to,
963 overriding IPsec's (large) default. This parameter is needed
964 only in special situations. This KLIPS option has no effect on
965 NETKEY, Windows or BSD stacks.
966
969 The system automatically defines several conns to implement default
970 policy groups. These are used to enable the establishing of Opportu‐
971 nitic Encryption IPsec tunnels. That is, setting up IPsec tunnels with
972 peers you have no pre-arranged configuration with. Opportunistic
973 Encryption is currently only supported using the KLIPS or KLIPSNG
974 (mast) stack, and should not be enabled when using NETKEY, Windows or
975 BSD stacks.
976 Each can be overridden by explicitly defining a new conn with the same
979 name. If the new conn has auto=ignore, the definition is suppressed.
980 Here are the automatically supplied definitions.
983 conn clear
987 type=passthrough
988 authby=never
989 left=%defaultroute
990 right=%group
991 auto=route
992 conn clear-or-private
994 type=passthrough
995 left=%defaultroute
996 leftid=%myid
997 right=%opportunisticgroup
998 failureshunt=passthrough
999 keyingtries=3
1000 ikelifetime=1h
1001 keylife=1h
1002 rekey=no
1003 auto=route
1004 conn private-or-clear
1006 type=tunnel
1007 left=%defaultroute
1008 leftid=%myid
1009 right=%opportunisticgroup
1010 failureshunt=passthrough
1011 keyingtries=3
1012 ikelifetime=1h
1013 keylife=1h
1014 rekey=no
1015 auto=route
1016 conn private
1018 type=tunnel
1019 left=%defaultroute
1020 leftid=%myid
1021 right=%opportunisticgroup
1022 failureshunt=drop
1023 keyingtries=3
1024 ikelifetime=1h
1025 keylife=1h
1026 rekey=no
1027 auto=route
1028 conn block
1030 type=reject
1031 authby=never
1032 left=%defaultroute
1033 right=%group
1034 auto=route
1035 # default policy
1037 conn packetdefault
1038 type=tunnel
1039 left=%defaultroute
1040 leftid=%myid
1041 left=0.0.0.0/0
1042 right=%opportunistic
1043 failureshunt=passthrough
1044 keyingtries=3
1045 ikelifetime=1h
1046 keylife=1h
1047 rekey=no
1048 auto=route
1049 These conns are not affected by anything in conn %default. They will
1053 only work if %defaultroute works. The leftid will be the interfaces IP
1054 address; this requires that reverse DNS records be set up properly.
1055 The implicit conns are defined after all others. It is appropriate and
1058 reasonable to use also=private-or-clear (for example) in any other
1059 opportunistic conn.
1060
1063 The optional files under /etc/ipsec.d/policy, including
1064 /etc/ipsec.d/policies/clear
1068 /etc/ipsec.d/policies/clear-or-private
1069 /etc/ipsec.d/policies/private-or-clear
1070 /etc/ipsec.d/policies/private
1071 /etc/ipsec.d/policies/block
1072 may contain policy group configuration information to supplement
1077 ipsec.conf. Their contents are not security-sensitive.
1078 These files are text files. Each consists of a list of CIDR blocks, one
1081 per line. White space followed by # followed by anything to the end of
1082 the line is a comment and is ignored, as are empty lines.
1083 A connection in /etc/ipsec.conf which has right=%group or right=%oppor‐
1086 tunisticgroup is a policy group connection. When a policy group file of
1087 the same name is loaded, with
1088 ipsec auto --rereadgroups
1091 or at system start, the connection is instantiated such that each CIDR
1094 block serves as an instance's right value. The system treats the
1095 resulting instances as normal connections.
1096 For example, given a suitable connection definition private, and the
1099 file /etc/ipsec.d/policy/private with an entry 192.0.2.3, the system
1100 creates a connection instance private#192.0.2.3. This connection inher‐
1101 its all details from private, except that its right client is
1102 192.0.2.3.
1103
1106 The standard Openswan install includes several policy groups which pro‐
1107 vide a way of classifying possible peers into IPsec security classes:
1108 private (talk encrypted only), private-or-clear (prefer encryption),
1109 clear-or-private (respond to requests for encryption), clear and block.
1110 Implicit policy groups apply to the local host only, and are imple‐
1111 mented by the IMPLICIT CONNECTIONS described above.
1112
1115 When choosing a connection to apply to an outbound packet caught with a
1116 %trap, the system prefers the one with the most specific eroute that
1117 includes the packet's source and destination IP addresses. Source sub‐
1118 nets are examined before destination subnets. For initiating, only
1119 routed connections are considered. For responding, unrouted but added
1120 connections are considered.
1121 When choosing a connection to use to respond to a negotiation which
1124 doesn't match an ordinary conn, an opportunistic connection may be
1125 instantiated. Eventually, its instance will be /32 -> /32, but for ear‐
1126 lier stages of the negotiation, there will not be enough information
1127 about the client subnets to complete the instantiation.
1128
1131 /etc/ipsec.conf
1132 /etc/ipsec.d/policies/clear
1133 /etc/ipsec.d/policies/clear-or-private
1134 /etc/ipsec.d/policies/private-or-clear
1135 /etc/ipsec.d/policies/private
1136 /etc/ipsec.d/policies/block
1137
1141 ipsec(8), ipsec_ttoaddr(8), ipsec_whack(8), ipsec_auto(8), ipsec_man‐
1142 ual(8), ipsec_rsasigkey(8)
1143
1146 Designed for the FreeS/WAN project <http://www.freeswan.org:
1147 http://www.freeswan.org> by Henry Spencer.
1148
1151 When type or failureshunt is set to drop or reject, Openswan blocks
1152 outbound packets using eroutes, but assumes inbound blocking is handled
1153 by the firewall. Openswan offers firewall hooks via an “updown” script.
1154 However, the default ipsec _updown provides no help in controlling a
1155 modern firewall.
1156 The use of %any with the protoport= option is ambiguous. Should the SA
1159 permits any port through or should the SA negotiate any single port
1160 through? The first is a basic conn with a wildcard. The second is a
1161 template. The second is the current behaviour, and it's wrong for quite
1162 a number of uses involving TCP. The keyword %one may be introduced in
1163 the future to seperate these two cases.
1164 Including attributes of the keying channel (authentication methods,
1167 ikelifetime, etc.) as an attribute of a connection, rather than of a
1168 participant pair, is dubious and incurs limitations.
1169 Ipsec_manual is not nearly as generous about the syntax of subnets,
1172 addresses, etc. as the usual Openswan user interfaces. Four-component
1173 dotted-decimal must be used for all addresses. It is smart enough to
1174 translate bit-count netmasks to dotted-decimal form.
1175 It would be good to have a line-continuation syntax, especially for the
1178 very long lines involved in RSA signature keys.
1179 The ability to specify different identities, authby, and public keys
1182 for different automatic-keyed connections between the same participants
1183 is misleading; this doesn't work dependably because the identity of the
1184 participants is not known early enough. This is especially awkward for
1185 the “Road Warrior” case, where the remote IP address is specified as
1186 0.0.0.0, and that is considered to be the “participant” for such con‐
1187 nections.
1188 In principle it might be necessary to control MTU on an inter‐
1191 face-by-interface basis, rather than with the single global override
1192 that overridemtu provides.
1193 A number of features which could be implemented in both manual and
1196 automatic keying actually are not yet implemented for manual keying.
1197 This is unlikely to be fixed any time soon.
1198 If conns are to be added before DNS is available, left=FQDN, leftnex‐
1201 top=FQDN, and leftrsasigkey=%dnsonload will fail. ipsec_pluto(8) does
1202 not actually use the public key for our side of a conn but it isn't
1203 generally known at a add-time which side is ours (Road Warrior and
1204 Opportunistic conns are currently exceptions).
1205 The myid option does not affect explicit ipsec auto --add or ipsec
1208 auto --replace commands for implicit conns.
1209 IPSEC.CONF(5)