Provided by: openswan_2.6.37-1_i386 bug

NAME

       ipsec.conf - IPsec configuration and connections

DESCRIPTION

       The optional ipsec.conf file specifies most configuration and control
       information for the Openswan IPsec subsystem. (The major exception is
       secrets for authentication; see ipsec.secrets(5).) Its contents are not
       security-sensitive unless manual keying is being done for more than
       just testing, in which case the encryption/authentication keys in the
       descriptions for the manually-keyed connections are very sensitive (and
       those connection descriptions are probably best kept in a separate
       file, via the include facility described below).

       The file is a text file, consisting of one or more sections. White
       space followed by # followed by anything to the end of the line is a
       comment and is ignored, as are empty lines which are not within a
       section.

       A line which contains include and a file name, separated by white
       space, is replaced by the contents of that file, preceded and followed
       by empty lines. If the file name is not a full pathname, it is
       considered to be relative to the directory containing the including
       file. Such inclusions can be nested. Only a single filename may be
       supplied, and it may not contain white space, but it may include shell
       wildcards (see sh(1)); for example:

       include ipsec.*.conf

       The intention of the include facility is mostly to permit keeping
       information on connections, or sets of connections, separate from the
       main configuration file. This permits such connection descriptions to
       be changed, copied to the other security gateways involved, etc.,
       without having to constantly extract them from the configuration file
       and then insert them back into it. Note also the also and alsoflip
       parameters (described below) which permit splitting a single logical
       section (e.g. a connection description) into several actual sections.

       The first significant line of the file must specify the version of this
       specification that it conforms to:

       version 2

       A section begins with a line of the form:

       type name

       where type indicates what type of section follows, and name is an
       arbitrary name which distinguishes the section from others of the same
       type. (Names must start with a letter and may contain only letters,
       digits, periods, underscores, and hyphens.) All subsequent non-empty
       lines which begin with white space are part of the section; comments
       within a section must begin with white space too. There may be only one
       section of a given type with a given name.

       Lines within the section are generally of the form

            parameter=value

       (note the mandatory preceding white space). There can be white space on
       either side of the =. Parameter names follow the same syntax as section
       names, and are specific to a section type. Unless otherwise explicitly
       specified, no parameter name may appear more than once in a section.

       An empty value stands for the system default value (if any) of the
       parameter, i.e. it is roughly equivalent to omitting the parameter line
       entirely. A value may contain white space only if the entire value is
       enclosed in double quotes ("); a value cannot itself contain a double
       quote, nor may it be continued across more than one line.

       Numeric values are specified to be either an "integer" (a sequence of
       digits) or a "decimal number" (sequence of digits optionally followed
       by `.' and another sequence of digits).

       There is currently one parameter which is available in any type of
       section:

       also
           the value is a section name; the parameters of that section are
           appended to this section, as if they had been written as part of
           it. The specified section must exist, must follow the current one,
           and must have the same section type. (Nesting is permitted, and
           there may be more than one also in a single section, although it is
           forbidden to append the same section more than once.) This allows,
           for example, keeping the encryption keys for a connection in a
           separate file from the rest of the description, by using both an
           also parameter and an include line. (Caution, see BUGS below for
           some restrictions.)

       alsoflip
           can be used in a conn section. It acts like an also that flips the
           referenced section's entries left-for-right.

       Parameter names beginning with x- (or X-, or x_, or X_) are reserved
       for user extensions and will never be assigned meanings by IPsec.
       Parameters with such names must still observe the syntax rules (limits
       on characters used in the name; no white space in a non-quoted value;
       no newlines or double quotes within the value). All other as-yet-unused
       parameter names are reserved for future IPsec improvements.

       A section with name %default specifies defaults for sections of the
       same type. For each parameter in it, any section of that type which
       does not have a parameter of the same name gets a copy of the one from
       the %default section. There may be multiple %default sections of a
       given type, but only one default may be supplied for any specific
       parameter name, and all %default sections of a given type must precede
       all non-%default sections of that type.  %default sections may not
       contain also or alsoflip parameters.

       Currently there are two types of section: a config section specifies
       general configuration information for IPsec, while a conn section
       specifies an IPsec connection.

CONN SECTIONS

       A conn section contains a connection specification, defining a network
       connection to be made using IPsec. The name given is arbitrary, and is
       used to identify the connection to ipsec_auto(8) and ipsec_manual(8).
       Here's a simple example:

           conn snt
                left=10.11.11.1
                leftsubnet=10.0.1.0/24
                leftnexthop=172.16.55.66
                leftsourceip=10.0.1.1
                right=192.168.22.1
                rightsubnet=10.0.2.0/24
                rightnexthop=172.16.88.99
                rightsourceip=10.0.2.1
                keyingtries=%forever

       A note on terminology... In automatic keying, there are two kinds of
       communications going on: transmission of user IP packets, and
       gateway-to-gateway negotiations for keying, rekeying, and general
       control. The data path (a set of "IPsec SAs") used for user packets is
       herein referred to as the "connection"; the path used for negotiations
       (built with "ISAKMP SAs") is referred to as the "keying channel".

       To avoid trivial editing of the configuration file to suit it to each
       system involved in a connection, connection specifications are written
       in terms of left and right participants, rather than in terms of local
       and remote. Which participant is considered left or right is arbitrary;
       IPsec figures out which one it is being run on based on internal
       information. This permits using identical connection specifications on
       both ends. There are cases where there is no symmetry; a good
       convention is to use left for the local side and right for the remote
       side (the first letters are a good mnemonic).

       Many of the parameters relate to one participant or the other; only the
       ones for left are listed here, but every parameter whose name begins
       with left has a right counterpart, whose description is the same but
       with left and right reversed.

       Parameters are optional unless marked "(required)"; a parameter
       required for manual keying need not be included for a connection which
       will use only automatic keying, and vice versa.

   CONN PARAMETERS: GENERAL
       The following parameters are relevant to both automatic and manual
       keying. Unless otherwise noted, for a connection to work, in general it
       is necessary for the two ends to agree exactly on the values of these
       parameters.

       connaddrfamily
           the connection addrress family of the connection; currently the
           accepted values are ipv4 (the default); or ipv6. This option is
           confusing, especially when doing IPv4-in-IPv6 or IPv6-in-IPv4
           tunnels. The developers hope to remove this option in the near
           future for proper auto-detection. For now, set connaddrfamily= to
           the family of the *subnet= options, and if those are not defined,
           to the family of the left=/right= options.

           IPv6 is supported with NETKEY since openswan 2.4 and with KLIPS
           since Openswan 2.6.33

       type
           the type of the connection; currently the accepted values are
           tunnel (the default) signifying a host-to-host, host-to-subnet, or
           subnet-to-subnet tunnel; transport, signifying host-to-host
           transport mode; passthrough, signifying that no IPsec processing
           should be done at all; drop, signifying that packets should be
           discarded; and reject, signifying that packets should be discarded
           and a diagnostic ICMP returned.

       left
           (required) the IP address of the left participant's public-network
           interface, in any form accepted by ipsec_ttoaddr(3). Currently,
           IPv4 and IPv6 IP addresses are supported. There are several magic
           values. If it is %defaultroute, and the config setup section's,
           interfaces specification contains %defaultroute, left will be
           filled in automatically with the local address of the default-route
           interface (as determined at IPsec startup time); this also
           overrides any value supplied for leftnexthop. (Either left or right
           may be %defaultroute, but not both.) The value %any signifies an
           address to be filled in (by automatic keying) during negotiation.
           The value %opportunistic signifies that both left and leftnexthop
           are to be filled in (by automatic keying) from DNS data for left's
           client. The value can also contain the interface name, which will
           then later be used to obtain the IP address from to fill in. For
           example %ppp0 The values %group and %opportunisticgroup makes this
           a policy group conn: one that will be instantiated into a regular
           or opportunistic conn for each CIDR block listed in the policy
           group file with the same name as the conn.

           If using IP addresses in combination with NAT, always use the
           actual local machine's (NAT'ed) IP address, and if the remote (eg
           right=) is NAT'ed as well, the remote's public (not NAT'ed) IP
           address. Note that this makes the configuration no longer
           symmetrical on both sides, so you cannot use an identical
           configuration file on both hosts.

       leftsubnet
           private subnet behind the left participant, expressed as
           network/netmask (actually, any form acceptable to
           ipsec_ttosubnet(3)); Currentlly, IPv4 and IPv6 ranges are
           supported. if omitted, essentially assumed to be left/32,
           signifying that the left end of the connection goes to the left
           participant only

           It supports two magic shorthands vhost: and vnet:, which can list
           subnets in the same syntax as virtual_private. The value %priv
           expands to the networks specified in virtual_private. The value %no
           means no subnet. A common use for allowing roadwarrios to come in
           on public IPs or via accepted NATed networks from RFC1918 is to use
           leftsubnet=vhost:%no,%priv. The vnet: option can be used to allow
           RFC1918 subnets without hardcoding them. When using vnet the
           connection will instantiate, allowing for multiple tunnels with
           different subnets.

       leftsubnets
           specify multiple private subnets behind the left participant,
           expressed as { networkA/netmaskA networkB/netmaskB [...]  } If both
           a leftsubnets= and rightsubnets= is defined, all combinations of
           subnet tunnels will be instantiated. You cannot use leftsubnet and
           leftsubnets together. For examples see testing/pluto/multinet-*.

       leftprotoport
           allowed protocols and ports over connection, also called Port
           Selectors. The argument is in the form protocol, which can be a
           number or a name that will be looked up in /etc/protocols, such as
           leftprotoport=icmp, or in the form of protocol/port, such as
           tcp/smtp. Ports can be defined as a number (eg. 25) or as a name
           (eg smtp) which will be looked up in /etc/services. A special
           keyword %any can be used to allow all ports of a certain protocol.
           The most common use of this option is for L2TP connections to only
           allow l2tp packets (UDP port 1701), eg: leftprotoport=17/1701. Some
           clients, notably older Windows XP and some Mac OSX clients, use a
           random high port as source port. In those cases
           rightprotoport=17/%any can be used to allow all UDP traffic on the
           connection. Note that this option is part of the proposal, so it
           cannot be arbitrarily left out if one end does not care about the
           traffic selection over this connection - both peers have to agree.
           The Port Selectors show up in the output of ipsec eroute and ipsec
           auto --status eg:"l2tp":
           193.110.157.131[@aivd.xelernace.com]:7/1701...%any:17/1701 This
           option only filters outbound traffic. Inbound traffic selection
           must still be based on firewall rules activated by an updown
           script. The variablees $PLUTO_MY_PROTOCOL, $PLUTO_PEER_PROTOCOL,
           $PLUTO_MY_PORT, and $PLUTO_PEER_PORT are available for use in
           updown scripts. Older workarounds for bugs involved a setting of
           17/0 to denote any single UDP port (not UDP port 0). Some clients,
           most notably OSX, uses a random high port, instead of port 1701 for
           L2TP.

       leftnexthop
           next-hop gateway IP address for the left participant's connection
           to the public network; defaults to %direct (meaning right). If the
           value is to be overridden by the left=%defaultroute method (see
           above), an explicit value must not be given. If that method is not
           being used, but leftnexthop is %defaultroute, and
           interfaces=%defaultroute is used in the config setup section, the
           next-hop gateway address of the default-route interface will be
           used. The magic value %direct signifies a value to be filled in (by
           automatic keying) with the peer's address. Relevant only locally,
           other end need not agree on it.

       leftsourceip
           the IP address for this host to use when transmitting a packet to
           the other side of this link. Relevant only locally, the other end
           need not agree. This option is used to make the gateway itself use
           its internal IP, which is part of the leftsubnet, to communicate to
           the rightsubnet or right. Otherwise, it will use its nearest IP
           address, which is its public IP address. This option is mostly used
           when defining subnet-subnet connections, so that the gateways can
           talk to each other and the subnet at the other end, without the
           need to build additional host-subnet, subnet-host and host-host
           tunnels. Both IPv4 and IPv6 addresses are supported.

       leftupdown
           what "updown" script to run to adjust routing and/or firewalling
           when the status of the connection changes (default ipsec _updown).
           May include positional parameters separated by white space
           (although this requires enclosing the whole string in quotes);
           including shell metacharacters is unwise. An example to enable
           routing when using the NETKEY stack, one can use:

           leftupdown="ipsec _updown --route yes"

           See ipsec_pluto(8) for details. Relevant only locally, other end
           need not agree on it.

       leftfirewall
           This option is obsolete and should not used anymore.

       If one or both security gateways are doing forwarding firewalling
       (possibly including masquerading), and this is specified using the
       firewall parameters, tunnels established with IPsec are exempted from
       it so that packets can flow unchanged through the tunnels. (This means
       that all subnets connected in this manner must have distinct,
       non-overlapping subnet address blocks.) This is done by the default
       updown script (see ipsec_pluto(8)).

       The implementation of this makes certain assumptions about firewall
       setup, and the availability of the Linux Advanced Routing tools. In
       situations calling for more control, it may be preferable for the user
       to supply his own updown script, which makes the appropriate
       adjustments for his system.

   CONN PARAMETERS: AUTOMATIC KEYING
       The following parameters are relevant only to automatic keying, and are
       ignored in manual keying. Unless otherwise noted, for a connection to
       work, in general it is necessary for the two ends to agree exactly on
       the values of these parameters.

       auto
           what operation, if any, should be done automatically at IPsec
           startup; currently-accepted values are add (signifying an ipsec
           auto --add), route (signifying that plus an ipsec auto --route),
           start (signifying that plus an ipsec auto --up), manual (signifying
           an ipsec manual --up), and ignore (also the default) (signifying no
           automatic startup operation). See the config setup discussion
           below. Relevant only locally, other end need not agree on it (but
           in general, for an intended-to-be-permanent connection, both ends
           should use auto=start to ensure that any reboot causes immediate
           renegotiation).

       authby
           how the two security gateways should authenticate each other;
           acceptable values are secret for shared secrets, rsasig for RSA
           digital signatures (the default), secret|rsasig for either, and
           never if negotiation is never to be attempted or accepted (useful
           for shunt-only conns). Digital signatures are superior in every way
           to shared secrets.

       ike
           IKE encryption/authentication algorithm to be used for the
           connection (phase 1 aka ISAKMP SA). The format is
           "cipher-hash;modpgroup, cipher-hash;modpgroup, ..."  Any left out
           option will be filled in with all allowed default options. Multiple
           proposals are separated by a comma. If an ike= line is specified,
           no other received proposals will be accepted. Formerly there was a
           distinction (by using a "!"  symbol) between "strict mode" or not.
           That mode has been obsoleted. If an ike= option is specified, the
           mode is always strict, meaning no other received proposals will be
           accepted. Some examples are ike=3des-sha1,aes-sha1, ike=aes,
           ike=aes128-md5;modp2048, ike=aes128-sha1;dh22,
           ike=3des-md5;modp1024,aes-sha1;modp1536 or ike=modp1536. The
           options must be suitable as a value of ipsec_spi(8)'s --ike option.
           The default is to use IKE, and to allow all combinations of:

                               cipher:                 3des or aes
                               hash:                   sha1 or md5
                               pfsgroup (DHgroup):     modp1024 or modp1536

           If Openswan was compiled with extra INSECURE and BROKEN options,
           then the des (1des) and null cipher, as well as modp768 are
           available. This turns your VPN into a joke. Do not enable these
           options.

           If openswan was compiled with USE_MODP_RFC5114 support, then
           Diffie-Hellman groups 22, 23 and 24 are also implemented as per
           RFC-5114. Instead of the modp key syntax, use the "dh" keyword, for
           example ike=3des-sha1;dh23

       phase2
           Sets the type of SA that will be produced. Valid options are: esp
           for encryption (the default), and ah for authentication only.

       phase2alg
           Specifies the algorithms that will be offered/accepted for a phase2
           negotiation. If not specified, a secure set of defaults will be
           used. Sets are separated using comma's.

           The default values are the same as for ike= Note also that not all
           ciphers available to the kernel (eg through CryptoAPI) are
           necessarilly supported here.

           The format for ESP is ENC-AUTH followed by an optional PFSgroup.
           For instance, "3des-md5" or "aes256-sha1;modp2048" or
           "aes-sha1,aes-md5".

           For RFC-5114 DH groups, use the "dh" keyword, eg "aes256-sha1;dh23"

           The format for AH is AUTH followed by an optional PFSgroup. For
           instance, "md5" or "sha1;modp1536".

           A special case is AES CCM, which uses the syntax of
           "phase2alg=aes_ccm_a-152-null"

       esp
           This option is obsolete. Please use phase2alg instead.

       ah
           AH authentication algorithm to be used for the connection, e.g
           here.  hmac-md5 The options must be suitable as a value of
           ipsec_spi(8)'s --ah option. The default is not to use AH. If for
           some (invalid) reason you still think you need AH, please use esp
           with the null encryption cipher instead. Note also that not all
           ciphers available to the kernel (eg through CryptoAPI) are
           necessarilly supported here.

       ikev2
           IKEv2 (RFC4309) settings to be used. Currently the accepted values
           are permit, (the default) signifying no IKEv2 should be
           transmitted, but will be accepted if the other ends initiates to us
           with IKEv2; never or no signifying no IKEv2 negotiation should be
           transmitted or accepted; propose or yes signifying that we permit
           IKEv2, and also use it as the default to initiate; insist,
           signifying we only accept and receive IKEv2 - IKEv1 negotiations
           will be rejected.

           If the ikev2= setting is set to permit or propose, Openswan will
           try and detect a "bid down" attack from IKEv2 to IKEv1. Since there
           is no standard for transmitting the IKEv2 capability with IKEv1,
           Openswan uses a special Vendor ID "CAN-IKEv2". If a fall back from
           IKEv2 to IKEv1 was detected, and the IKEv1 negotiation contains
           Vendor ID "CAN-IKEv2", Openswan will immediately attempt and IKEv2
           rekey and refuse to use the IKEv1 connection. With an ikev2=
           setting of insist, no IKEv1 negotiation is allowed, and no bid down
           attack is possible.

       sareftrack
           Set the method of tracking reply packets with SArefs when using an
           SAref compatible stack. Currently only the mast stack supports
           this. Acceptable values are yes (the default), no or conntrack.
           This option is ignored when SArefs are not supported. This option
           is passed as PLUTO_SAREF_TRACKING to the updown script which makes
           the actual decisions whether to perform any iptables/ip_conntrack
           manipulation. A value of yes means that an IPSEC mangle table will
           be created. This table will be used to match reply packets. A value
           of conntrack means that additionally, subsequent packets using this
           connection will be marked as well, reducing the lookups needed to
           find the proper SAref by using the ip_conntrack state. A value of
           no means no IPSEC mangle table is created, and SAref tracking is
           left to a third-party (kernel) module. In case of a third party
           module, the SArefs can be relayed using the HAVE_STATSD deamon.

       leftid
           how the left participant should be identified for authentication;
           defaults to left. Can be an IP address (in any ipsec_ttoaddr(3)
           syntax) or a fully-qualified domain name preceded by @ (which is
           used as a literal string and not resolved). The magic value
           %fromcert causes the ID to be set to a DN taken from a certificate
           that is loaded. Prior to 2.5.16, this was the default if a
           certificate was specified. The magic value %none sets the ID to no
           ID. This is included for completeness, as the ID may have been set
           in the default conn, and one wishes for it to default instead of
           being explicitly set. The magic value %myid stands for the current
           setting of myid. This is set in config setup or by ipsec_whack(8)),
           or, if not set, it is the IP address in %defaultroute (if that is
           supported by a TXT record in its reverse domain), or otherwise it
           is the system's hostname (if that is supported by a TXT record in
           its forward domain), or otherwise it is undefined.

       leftrsasigkey
           the left participant's public key for RSA signature authentication,
           in RFC 2537 format using ipsec_ttodata(3) encoding. The magic value
           %none means the same as not specifying a value (useful to override
           a default). The value %dnsondemand (the default) means the key is
           to be fetched from DNS at the time it is needed. The value
           %dnsonload means the key is to be fetched from DNS at the time the
           connection description is read from ipsec.conf; currently this will
           be treated as %none if right=%any or right=%opportunistic. The
           value %dns is currently treated as %dnsonload but will change to
           %dnsondemand in the future. The identity used for the left
           participant must be a specific host, not %any or another magic
           value. The value %cert will load the information required from a
           certificate defined in %leftcert and automatically define leftid
           for you.  Caution: if two connection descriptions specify different
           public keys for the same leftid, confusion and madness will ensue.

       leftrsasigkey2
           if present, a second public key. Either key can authenticate the
           signature, allowing for key rollover.

       leftcert
           If you are using leftrsasigkey=%cert this defines the certificate
           you would like to use. It should point to a X.509 encoded
           certificate file. If you do not specify a full pathname, by default
           it will look in /etc/ipsec.d/certs. If openswan has been compiled
           with USE_LIBNSS=true, then openswan will also check the NSS
           database for RSA keys. These can be software or hardware.

       leftca
           specifies the authorized Certificate Authority (CA) that signed the
           certificate of the peer. If undefined, it defaults to the CA that
           signed the certificate specified in leftcert. The special
           rightca=%same is implied when not specifying a rightca and means
           that only peers with certificates signed by the same CA as the
           leftca will be allowed. This option is only useful in complex multi
           CA certificate situations. When using a single CA, it can be safely
           omitted for both left and right.

       leftsendcert
           This option configures when Openswan will send X.509 certificates
           to the remote host. Acceptable values are yes|always (signifying
           that we should always send a certificate), ifasked (signifying that
           we should send a certificate if the remote end asks for it), and
           no|never (signifying that we will never send a X.509 certificate).
           The default for this option is ifasked which may break
           compatibility with other vendor's IPSec implementations, such as
           Cisco and SafeNet. If you find that you are getting errors about no
           ID/Key found, you likely need to set this to always. This per-conn
           option replaces the obsolete global nocrsend option.

       leftxauthserver
           Left is an XAUTH server. This can use PAM for authentication or md5
           passwords in /etc/ipsec.d/passwd. These are additional credentials
           to verify the user identity, and should not be confused with the
           XAUTH group secret, which is just a regular PSK defined in
           ipsec.secrets. The other side of the connection should be
           configured as rightxauthclient. XAUTH connections cannot rekey, so
           rekey=no should be specified in this conn. For further details on
           how to compile and use XAUTH, see README.XAUTH. Acceptable values
           are yes or no (the default).

       leftxauthclient
           Left is an XAUTH client. The xauth connection will have to be
           started interactively and cannot be configured using auto=start.
           Instead, it has to be started from the commandline using ipsec auto
           --up connname. You will then be prompted for the username and
           password. To setup an XAUTH connection non-interactively, which
           defeats the whole purpose of XAUTH, but is regularly requested by
           users, it is possible to use a whack command - ipsec whack --name
           baduser --ipsecgroup-xauth --xauthname badusername --xauthpass
           password --initiate The other side of the connection should be
           configured as rightxauthserver. Acceptable values are yes or no
           (the default).

       leftxauthusername
           The XAUTH username associated with this XAUTH connection. The XAUTH
           password can be configured in the ipsec.secrets file.

       leftmodecfgserver
           Left is a Mode Config server. It can push network configuration to
           the client. Acceptable values are yes or no (the default).

       leftmodecfgclient
           Left is a Mode Config client. It can receive network configuration
           from the server. Acceptable values are yes or no (the default).

       modecfgpull
           Pull the Mode Config network information from the server.
           Acceptable values are yes or no (the default).

       modecfgdns1, modecfgdns2, modecfgwins1, modecfgwins2
           Specify the IP address for DNS or WINS servers for the client to
           use.

       remote_peer_type
           Set the remote peer type. This can enable additional processing
           during the IKE negotiation. Acceptable values are cisco or ietf
           (the default). When set to cisco, support for Cisco IPsec gateway
           redirection and Cisco obtained DNS and domainname are enabled. This
           includes automatically updating (and restoring) /etc/resolv.conf.
           These options require that XAUTH is also enabled on this
           connection.

       nm_configured
           Mark this connection as controlled by Network Manager. Acceptable
           values are yes or no (the default). Currently, setting this to yes
           will cause openswan to skip reconfiguring resolv.conf when used
           with XAUTH and ModeConfig.

       forceencaps
           In some cases, for example when ESP packets are filtered or when a
           broken IPsec peer does not properly recognise NAT, it can be useful
           to force RFC-3948 encapsulation.  forceencaps=yes forces the NAT
           detection code to lie and tell the remote peer that RFC-3948
           encapsulation (ESP in UDP port 4500 packets) is required. For this
           option to have any effect, the setup section option
           nat_traversal=yes needs to be set. Acceptable values are yes or no
           (the default).

       overlapip
           a boolean (yes/no) that determines, when *subnet=vhost: is used, if
           the virtual IP claimed by this states created from this connection
           can with states created from other connections.

           Note that connection instances created by the Opportunistic
           Encryption or PKIX (x.509) instantiation system are distinct
           internally. They will inherit this policy bit.

           The default is no.

           This feature is only available with kernel drivers that support SAs
           to overlapping conns. At present only the (klips)mast protocol
           stack supports this feature.

       dpddelay
           Set the delay (in seconds) between Dead Peer Dectection (RFC 3706)
           keepalives (R_U_THERE, R_U_THERE_ACK) that are sent for this
           connection (default 30 seconds). If dpddelay is set, dpdtimeout
           also needs to be set.

       dpdtimeout
           Set the length of time (in seconds) we will idle without hearing
           either an R_U_THERE poll from our peer, or an R_U_THERE_ACK reply.
           After this period has elapsed with no response and no traffic, we
           will declare the peer dead, and remove the SA (default 120
           seconds). If dpdtimeout is set, dpdaction also needs to be set.

       dpdaction
           When a DPD enabled peer is declared dead, what action should be
           taken.  hold (default) means the eroute will be put into %hold
           status, while clear means the eroute and SA with both be cleared.
           restart means the the SA will immediately be renegotiated, and
           restart_by_peer means that ALL SA's to the dead peer will
           renegotiated.

           dpdaction=clear is really only useful on the server of a Road
           Warrior config.

       pfs
           whether Perfect Forward Secrecy of keys is desired on the
           connection's keying channel (with PFS, penetration of the
           key-exchange protocol does not compromise keys negotiated earlier);
           Since there is no reason to ever refuse PFS, Openswan will allow a
           connection defined with pfs=no to use PFS anyway. Acceptable values
           are yes (the default) and no.

       pfsgroup
           This option is obsoleted, please use phase2alg if you need the pfs
           to be different from phase1 (the default) using:
           phase2alg=aes128-md5;modp1024

       aggrmode
           Use Aggressive Mode instead of Main Mode. Aggressive Mode is less
           secure, and vulnerable to Denial Of Service attacks. It is also
           vulnerable to brute force attacks with software such as ikecrack.
           It should not be used, and it should especially not be used with
           XAUTH and group secrets (PSK). If the remote system administrator
           insists on staying irresponsible, enable this option.

           Aggressive Mode is further limited to only proposals with one DH
           group as there is no room to negotiate the DH group. Therefor it is
           mandatory for Aggressive Mode connections that both ike= and
           phase2alg= options are specified with only fully specified proposal
           using one DH group. Acceptable values are yes or no (the default).

           The ISAKMP SA is created in exchange 1 in aggressive mode. Openswan
           has to send the exponent during that exchange, so it has to know
           what DH group to use before starting. This is why you can not have
           multiple DH groups in aggressive mode. In IKEv2, which uses a
           similar method to IKEv1 Aggressive Mode, there is a message to
           convey the DH group is wrong, and so an IKEv2 connection can
           actually recover from picking the wrong DH group by restarting its
           negotiation.

       salifetime
           how long a particular instance of a connection (a set of
           encryption/authentication keys for user packets) should last, from
           successful negotiation to expiry; acceptable values are an integer
           optionally followed by s (a time in seconds) or a decimal number
           followed by m, h, or d (a time in minutes, hours, or days
           respectively) (default 8h, maximum 24h). Normally, the connection
           is renegotiated (via the keying channel) before it expires. The two
           ends need not exactly agree on salifetime, although if they do not,
           there will be some clutter of superseded connections on the end
           which thinks the lifetime is longer.

           The keywords "keylife" and "lifetime" are aliases for "salifetime."

       rekey
           whether a connection should be renegotiated when it is about to
           expire; acceptable values are yes (the default) and no. The two
           ends need not agree, but while a value of no prevents Pluto from
           requesting renegotiation, it does not prevent responding to
           renegotiation requested from the other end, so no will be largely
           ineffective unless both ends agree on it.

       rekeymargin
           how long before connection expiry or keying-channel expiry should
           attempts to negotiate a replacement begin; acceptable values as for
           salifetime (default 9m). Relevant only locally, other end need not
           agree on it.

       rekeyfuzz
           maximum percentage by which rekeymargin should be randomly
           increased to randomize rekeying intervals (important for hosts with
           many connections); acceptable values are an integer, which may
           exceed 100, followed by a `%' (default set by ipsec_pluto(8),
           currently 100%). The value of rekeymargin, after this random
           increase, must not exceed salifetime. The value 0% will suppress
           time randomization. Relevant only locally, other end need not agree
           on it.

       keyingtries
           how many attempts (a whole number or %forever) should be made to
           negotiate a connection, or a replacement for one, before giving up
           (default %forever). The value %forever means "never give up"
           (obsolete: this can be written 0). Relevant only locally, other end
           need not agree on it.

       ikelifetime
           how long the keying channel of a connection (buzzphrase: "ISAKMP
           SA") should last before being renegotiated; acceptable values as
           for keylife (default set by ipsec_pluto(8), currently 1h, maximum
           24h). The two-ends-disagree case is similar to that of keylife.

       compress
           whether IPComp compression of content is proposed on the connection
           (link-level compression does not work on encrypted data, so to be
           effective, compression must be done before encryption); acceptable
           values are yes and no (the default). The two ends need not agree. A
           value of yes causes IPsec to propose both compressed and
           uncompressed, and prefer compressed. A value of no prevents IPsec
           from proposing compression; a proposal to compress will still be
           accepted.

       metric
           Set the metric for the routes to the ipsecX or mastX interface.
           This makes it possible to do host failover from another interface
           to ipsec using route management. This value is passed to the
           _updown scripts as PLUTO_METRIC. This option is only available with
           KLIPS or MAST on Linux. Acceptable values are positive numbers,
           with the default being 1.

       mtu
           Set the mtu for the route(s) to the remote endpoint and/or subnets.
           This is sometimes required when the overhead of the IPsec
           encapsultion would cause the packet the become too big for a router
           on the path. Since IPsec cannot trust any unauthenticated ICMP
           messages, PATH MTU discovery does not work. This can also be needed
           when using "6to4" IPV6 deployments, which adds another header on
           the packet size. Acceptable values are positive numbers. There is
           no default.

       disablearrivalcheck
           whether KLIPS's normal tunnel-exit check (that a packet emerging
           from a tunnel has plausible addresses in its header) should be
           disabled; acceptable values are yes and no (the default).
           Tunnel-exit checks improve security and do not break any normal
           configuration. Relevant only locally, other end need not agree on
           it.

       failureshunt
           what to do with packets when negotiation fails. The default is
           none: no shunt; passthrough, drop, and reject have the obvious
           meanings.

   CONN PARAMETERS: MANUAL KEYING
       This command was obsoleted around the same time that Al Gore invented
       the internet. ipsec manual was used in the jurassic period to load
       static keys into the kernel. There are no rational reasons to use this,
       and it is not supported anymore. If you need to create static SAs, then
       you can use ipsec spi and ipsec eroute when using KLIPS or ip xfrm or
       setkey when using NETKEY.

       No rational person uses static keys. They are not easier to use.
       REPEAT: they are not easier to use.

CONFIG SECTIONS

       At present, the only config section known to the IPsec software is the
       one named setup, which contains information used when the software is
       being started (see ipsec_setup(8)). Here's an example:

           config setup
                interfaces="ipsec0=eth1 ipsec1=ppp0"
                klipsdebug=none
                plutodebug=control
                protostack=auto
                manualstart=

       Parameters are optional unless marked "(required)".

       The currently-accepted parameter names in a config setup section are:

       myid
           the identity to be used for %myid.  %myid is used in the implicit
           policy group conns and can be used as an identity in explicit
           conns. If unspecified, %myid is set to the IP address in
           %defaultroute (if that is supported by a TXT record in its reverse
           domain), or otherwise the system's hostname (if that is supported
           by a TXT record in its forward domain), or otherwise it is
           undefined. An explicit value generally starts with ``@''.

       protostack
           decide which protocol stack is going to be used. Valid values are
           "auto", "klips", "netkey" and "mast". The "mast" stack is a
           variation for the klips stack.

       interfaces
           virtual and physical interfaces for IPsec to use: a single
           virtual=physical pair, a (quoted!) list of pairs separated by white
           space, or %none. One of the pairs may be written as %defaultroute,
           which means: find the interface d that the default route points to,
           and then act as if the value was ``ipsec0=d''.  %defaultroute is
           the default; %none must be used to denote no interfaces, or when
           using the NETKEY stack. If %defaultroute is used (implicitly or
           explicitly) information about the default route and its interface
           is noted for use by ipsec_manual(8) and ipsec_auto(8).)

       listen
           IP address to listen on (default depends on interfaces= setting).
           Currently only accepts one IP address.

       nat_traversal
           whether to accept/offer to support NAT (NAPT, also known as "IP
           Masqurade") workaround for IPsec. Acceptable values are: yes and no
           (the default). This parameter may eventually become per-connection.

       disable_port_floating
           whether to enable the newer NAT-T standards for port floating.
           Acceptable values are no (the default) and yes .

       force_keepalive
           whether to force sending NAT-T keep-alives to support NAT which are
           send to prevent the NAT router from closing its port when there is
           not enough traffic on the IPsec connection. Acceptable values are:
           yes and no (the default). This parameter may eventually become
           per-connection.

       keep_alive
           The delay (in seconds) for NAT-T keep-alive packets, if these are
           enabled using force_keepalive This parameter may eventually become
           per-connection.

       virtual_private
           contains the networks that are allowed as subnet= for the remote
           clients when using the vhost: or vnet: keywords in the subnet=
           parameters. In other words, the address ranges that may live behind
           a NAT router through which a client connects. This value is usually
           set to all the RFC-1918 address space, excluding the space used in
           the local subnet behind the NAT (An IP address cannot live at two
           places at once). IPv4 address ranges are denoted as %v4:a.b.c.d/mm
           and IPv6 is denoted as %v6:aaaa::bbbb:cccc:dddd:eeee/mm. One can
           exclude subnets by using the !. For example, if the VPN server is
           giving access to 192.168.1.0/24, this option should be set to:
           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. This parameter is only
           needed on the server side and not on the client side that resides
           behind the NAT router, as the client will just use its IP address
           for the inner IP setting. This parameter may eventually become
           per-connection. See also leftsubnet=

           Note: It seems that T-Mobile in the US and Rogers/Fido in Canada
           have started using 25.0.0.0/8 as their pre-NAT range. This range
           technically belows to the Defence Interoperable Network Services
           Authority (DINSA), an agency of the Ministry of Defence of the
           United Kingdom. The network range seems to not have been announced
           for decades, which is probably why these organisasions "borrowed"
           this range. To support roadwarriors on these 3G networks, you might
           have to add it to the virtual_private= line.

       oe
           a boolean (yes/no) that determines if Opportunistic Encryption will
           be enabled. Opportunistic Encryption is the term to describe using
           IPsec tunnels without prearrangement. It uses IPSECKEY or TXT
           records to announce public RSA keys for certain IP's or identities.

           For a complete description see
           /doc/draft-richardson-ipsec-opportunistic.txt,
           doc/opportunism-spec.txt and doc/opportunism.howto. See also the
           IETF BTNS working group and RFC4025.

           The default is no.

           This feature is only available with kernel drivers that support the
           caching of packets (%hold eroutes or equivalent) that allows us to
           respond to a packet from an unknown IP address. At present only the
           (klips)mast protocol stack supports this feature.

       nhelpers
           how many pluto helpers are started to help with cryptographic
           operations. Pluto will start (n-1) of them, where n is the number
           of CPU's you have (including hypherthreaded CPU's). A value of 0
           forces pluto to do all operations in the main process. A value of
           -1 tells pluto to perform the above calculation. Any other value
           forces the number to that amount.

       crlcheckinterval
           interval, specified in seconds, after which pluto will verify
           loaded X.509 CRL's for expiration. If any of the CRL's is expired,
           or if they previously failed to get updated, a new attempt at
           updating the CRL is made. The first attempt to update a CRL is
           started at two times the crlcheckinterval. If set to 0, which is
           also the default value if this option is not specified, CRL
           updating is disabled.

       strictcrlpolicy
           if not set, pluto is tolerant about missing or expired X.509
           Certificate Revocation Lists (CRL's), and will allow peer
           certificates as long as they do not appear on an expired CRL. When
           this option is enabled, all connections with an expired or missing
           CRL will be denied. Active connections will be terminated at rekey
           time. This setup is more secure, but also dangerous. If the CRL is
           fetched through an IPsec tunnel with a CRL that expired, the entire
           VPN server will be dead in the water until a new CRL is manually
           transferred to the machine (if it allows non-IPsec connections).
           Acceptable values are yes or no (the default).

       forwardcontrol
           This option is obsolete and ignored. Please use
           net.ipv4.ip_forward = 0 in /etc/sysctl.conf instead to control the
           ip forwarding behaviour.

       rp_filter
           This option is obsolete and ignored. Please use the
           net.ipv4.conf/[iface]/rp_filter = 0 options in /etc/sysctl.conf
           instead. This option is badly documented; it must be 0 in many
           cases for ipsec to function.

       syslog
           the syslog(2) "facility" name and priority to use for
           startup/shutdown log messages, default daemon.error.

       klipsdebug
           how much KLIPS debugging output should be logged. An empty value,
           or the magic value none, means no debugging output (the default).
           The magic value all means full output. Otherwise only the specified
           types of output (a quoted list, names separated by white space) are
           enabled; for details on available debugging types, see
           ipsec_klipsdebug(8). This KLIPS option has no effect on NETKEY,
           Windows or BSD stacks.

       plutodebug
           how much Pluto debugging output should be logged. An empty value,
           or the magic value none, means no debugging output (the default).
           The magic value all means full output. Otherwise only the specified
           types of output (a quoted list, names without the --debug- prefix,
           separated by white space) are enabled; for details on available
           debugging types, see ipsec_pluto(8).

       uniqueids
           whether a particular participant ID should be kept unique, with any
           new (automatically keyed) connection using an ID from a different
           IP address deemed to replace all old ones using that ID. Acceptable
           values are yes (the default) and no. Participant IDs normally are
           unique, so a new (automatically-keyed) connection using the same ID
           is almost invariably intended to replace an old one.

       plutorestartoncrash
           prevent pluto from restarting after it crashed. This option should
           only be used when debugging a crasher. It will prevent overwriting
           a core file on a new start, or a cascade of core files. This option
           is also required if used with plutostderrlog= to avoid clearing the
           logs of the crasher. Values can be yes (the default) or no.

       plutoopts
           additional options to pass to pluto upon startup. See
           ipsec_pluto(8).

       plutostderrlog
           do not use syslog, but rather log to stderr, and direct stderr to
           the argument file.

       pluto
           whether to start Pluto or not; Values are yes (the default) or no
           (useful only in special circumstances).

       plutowait
           should Pluto wait for each negotiation attempt that is part of
           startup to finish before proceeding with the next? Values are yes
           or no (the default).

       prepluto
           shell command to run before starting Pluto (e.g., to decrypt an
           encrypted copy of the ipsec.secrets file). It's run in a very
           simple way; complexities like I/O redirection are best hidden
           within a script. Any output is redirected for logging, so running
           interactive commands is difficult unless they use /dev/tty or
           equivalent for their interaction. Default is none.

       postpluto
           shell command to run after starting Pluto (e.g., to remove a
           decrypted copy of the ipsec.secrets file). It's run in a very
           simple way; complexities like I/O redirection are best hidden
           within a script. Any output is redirected for logging, so running
           interactive commands is difficult unless they use /dev/tty or
           equivalent for their interaction. Default is none.

       dumpdir
           in what directory should things started by setup (notably the Pluto
           daemon) be allowed to dump core? The empty value (the default)
           means they are not allowed to.

       fragicmp
           whether a tunnel's need to fragment a packet should be reported
           back with an ICMP message, in an attempt to make the sender lower
           his PMTU estimate; acceptable values are yes (the default) and no.
           This KLIPS option has no effect on NETKEY, Windows or BSD stacks.

       hidetos
           whether a tunnel packet's TOS field should be set to 0 rather than
           copied from the user packet inside; acceptable values are yes (the
           default) and no. This KLIPS option has no effect on NETKEY, Windows
           or BSD stacks.

       overridemtu
           value that the MTU of the ipsecn interface(s) should be set to,
           overriding IPsec's (large) default. This parameter is needed only
           in special situations. This KLIPS option has no effect on NETKEY,
           Windows or BSD stacks.

IMPLICIT CONNS

       The system automatically defines several conns to implement default
       policy groups. Each can be overridden by explicitly defining a new conn
       with the same name. If the new conn has auto=ignore, the definition is
       suppressed.

       Here are the automatically supplied definitions.

           conn clear
                type=passthrough
                authby=never
                left=%defaultroute
                right=%group
                auto=route

           conn clear-or-private
                type=passthrough
                left=%defaultroute
                leftid=%myid
                right=%opportunisticgroup
                failureshunt=passthrough
                keyingtries=3
                ikelifetime=1h
                salifetime=1h
                rekey=no
                auto=route

           conn private-or-clear
                type=tunnel
                left=%defaultroute
                leftid=%myid
                right=%opportunisticgroup
                failureshunt=passthrough
                keyingtries=3
                ikelifetime=1h
                salifetime=1h
                rekey=no
                auto=route

           conn private
                type=tunnel
                left=%defaultroute
                leftid=%myid
                right=%opportunisticgroup
                failureshunt=drop
                keyingtries=3
                ikelifetime=1h
                salifetime=1h
                rekey=no
                auto=route

           conn block
                type=reject
                authby=never
                left=%defaultroute
                right=%group
                auto=route

           # default policy
           conn packetdefault
                type=tunnel
                left=%defaultroute
                leftid=%myid
                left=0.0.0.0/0
                right=%opportunistic
                failureshunt=passthrough
                keyingtries=3
                ikelifetime=1h
                salifetime=1h
                rekey=no
                auto=route

       These conns are not affected by anything in conn %default. They will
       only work if %defaultroute works. The leftid will be the interfaces IP
       address; this requires that reverse DNS records be set up properly.

       The implicit conns are defined after all others. It is appropriate and
       reasonable to use also=private-or-clear (for example) in any other
       opportunistic conn.

POLICY GROUP FILES

       The optional files under /etc/ipsec.d/policy, including

           /etc/ipsec.d/policies/clear
           /etc/ipsec.d/policies/clear-or-private
           /etc/ipsec.d/policies/private-or-clear
           /etc/ipsec.d/policies/private
           /etc/ipsec.d/policies/block

       may contain policy group configuration information to supplement
       ipsec.conf. Their contents are not security-sensitive.

       These files are text files. Each consists of a list of CIDR blocks, one
       per line. White space followed by # followed by anything to the end of
       the line is a comment and is ignored, as are empty lines.

       A connection in ipsec.conf which has right=%group or
       right=%opportunisticgroup is a policy group connection. When a policy
       group file of the same name is loaded, with

            ipsec auto --rereadgroups

       or at system start, the connection is instantiated such that each CIDR
       block serves as an instance's right value. The system treats the
       resulting instances as normal connections.

       For example, given a suitable connection definition private, and the
       file /etc/ipsec.d/policy/private with an entry 192.0.2.3, the system
       creates a connection instance private#192.0.2.3.  This connection
       inherits all details from private, except that its right client is
       192.0.2.3.

DEFAULT POLICY GROUPS

       The standard Openswan install includes several policy groups which
       provide a way of classifying possible peers into IPsec security
       classes: private (talk encrypted only), private-or-clear (prefer
       encryption), clear-or-private (respond to requests for encryption),
       clear and block. Implicit policy groups apply to the local host only,
       and are implemented by the IMPLICIT CONNECTIONS described above.

CHOOSING A CONNECTION [THIS SECTION IS EXTREMELY OUT OF DATE

       When choosing a connection to apply to an outbound packet caught with a
       %trap, the system prefers the one with the most specific eroute that
       includes the packet's source and destination IP addresses. Source
       subnets are examined before destination subnets. For initiating, only
       routed connections are considered. For responding, unrouted but added
       connections are considered.

       When choosing a connection to use to respond to a negotiation which
       doesn't match an ordinary conn, an opportunistic connection may be
       instantiated. Eventually, its instance will be /32 -> /32, but for
       earlier stages of the negotiation, there will not be enough information
       about the client subnets to complete the instantiation.

FILES

           /etc/ipsec.conf
           /etc/ipsec.d/policies/clear
           /etc/ipsec.d/policies/clear-or-private
           /etc/ipsec.d/policies/private-or-clear
           /etc/ipsec.d/policies/private
           /etc/ipsec.d/policies/block

SEE ALSO

       ipsec(8), ipsec_ttoaddr(8), ipsec_auto(8), ipsec_manual(8),
       ipsec_rsasigkey(8)

HISTORY

       Designed for the FreeS/WAN project <http://www.freeswan.org> by Henry
       Spencer.

BUGS

       Before reporting new bugs, please ensure you are using the latest
       version of Openswan, and if not using KLIPS, please ensure you are
       using the latest kernel code for your IPsec stack.

       When type or failureshunt is set to drop or reject, Openswan blocks
       outbound packets using eroutes, but assumes inbound blocking is handled
       by the firewall. Openswan offers firewall hooks via an "updown" script.
       However, the default ipsec _updown provides no help in controlling a
       modern firewall.

       Including attributes of the keying channel (authentication methods,
       ikelifetime, etc.) as an attribute of a connection, rather than of a
       participant pair, is dubious and incurs limitations.

       The use of %any with the protoport= option is ambiguous. Should the SA
       permits any port through or should the SA negotiate any single port
       through? The first is a basic conn with a wildcard. The second is a
       template. The second is the current behaviour, and it's wrong for quite
       a number of uses involving TCP. The keyword %one may be introduced in
       the future to separate these two cases.

       ipsec_manual is not nearly as generous about the syntax of subnets,
       addresses, etc. as the usual Openswan user interfaces. Four-component
       dotted-decimal must be used for all addresses. It is smart enough to
       translate bit-count netmasks to dotted-decimal form.

       It would be good to have a line-continuation syntax, especially for the
       very long lines involved in RSA signature keys.

       First packet caching is only implemented for the KLIPS(NG) and MAST
       stacks. NETKEY returns POSIX-breaking responses, visiable as connect:
       Resource temporarily unavailable errors. This affects Opportunistic
       Encryption and DPD. Functionality on the BSD and Windows stacks is
       unknown.

       Some state information is only available when using KLIPS, and will
       return errors on other IPsec stacks. These include ipsec eroute, ipsec
       spi and ipsec look.

       Multiple L2TP clients behind the same NAT router, and multiple L2TP
       clients behind different NAT routers using the same Virtual IP is
       currently only working for the KLIPSNG stack.

       The ability to specify different identities, authby, and public keys
       for different automatic-keyed connections between the same participants
       is misleading; this doesn't work dependably because the identity of the
       participants is not known early enough. This is especially awkward for
       the "Road Warrior" case, where the remote IP address is specified as
       0.0.0.0, and that is considered to be the "participant" for such
       connections.

       In principle it might be necessary to control MTU on an
       interface-by-interface basis, rather than with the single global
       override that overridemtu provides. This feature is planned for a
       future release.

       A number of features which could be implemented in both manual and
       automatic keying actually are not yet implemented for manual keying.
       This is unlikely to be fixed any time soon.

       If conns are to be added before DNS is available, left=FQDN,
       leftnextop=FQDN, and leftrsasigkey=%dnsonload will fail.
       ipsec_pluto(8) does not actually use the public key for our side of a
       conn but it isn't generally known at a add-time which side is ours
       (Road Warrior and Opportunistic conns are currently exceptions).

       The myid option does not affect explicit
        ipsec auto --add or ipsec auto --replace commands for implicit conns.

[FIXME: source]                   04/21/2011                     IPSEC.CONF(5)