IPSEC.CONF(5) | [FIXME: manual] | IPSEC.CONF(5) |
NAME¶
ipsec.conf - IPsec configuration and connectionsDESCRIPTION¶
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: alsothe 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
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. connaddrfamilythe 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. autowhat 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:
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
cipher: 3des or aes hash: sha1 or md5 pfsgroup (DHgroup): modp1024 or modp1536
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=
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
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
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.04/21/2011 | [FIXME: source] |