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<HTML><HEAD><TITLE>Manpage of IPSEC.CONF</TITLE>
</HEAD><BODY>
<H1>IPSEC.CONF</H1>
Section: File Formats (5)<BR>Updated: 26 Nov 2001<BR><A HREF="#index">Index</A>
<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
<A NAME="lbAB">&nbsp;</A>
<H2>NAME</H2>
ipsec.conf - IPsec configuration and connections
<A NAME="lbAC">&nbsp;</A>
<H2>DESCRIPTION</H2>
The optional
<I>ipsec.conf</I>
file
specifies most configuration and control information for the
FreeS/WAN IPsec subsystem.
(The major exception is secrets for authentication;
see
<I><A HREF="ipsec.secrets.5.html">ipsec.secrets</A></I>(5).)
Its contents are not security-sensitive
<I>unless</I>
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).
<P>
The file is a text file, consisting of one or more
<I>sections</I>.
White space followed by
<B>#</B>
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.
<P>
A line which contains
<B>include</B>
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
<I><A HREF="sh.1.html">sh</A></I>(1));
for example:
<P>
<B>include</B>
<B>ipsec.*.conf</B>
<P>
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
<B>also</B>
and
<B>alsoflip</B>
parameters (described below) which permit splitting a single logical section
(e.g. a connection description) into several actual sections.
<P>
The first significant line of the file must specify the version
of this specification that it conforms to:
<P>
<B>version 2</B>
<P>
A section
begins with a line of the form:
<P>
<I>type</I>
<I>name</I>
<P>
where
<I>type</I>
indicates what type of section follows, and
<I>name</I>
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.
<P>
Lines within the section are generally of the form
<P>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<I>parameter</I><B>=</B><I>value</I>
<P>
(note the mandatory preceding white space).
There can be white space on either side of the
<B>=</B>.
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.
<P>
An empty
<I>value</I>
stands for the system default value (if any) of the parameter,
i.e. it is roughly equivalent to omitting the parameter line entirely.
A
<I>value</I>
may contain white space only if the entire
<I>value</I>
is enclosed in double quotes (<B>&quot;</B>);
a
<I>value</I>
cannot itself contain a double quote,
nor may it be continued across more than one line.
<P>
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).
<P>
There is currently one parameter which is available in any type of
section:
<DL COMPACT>
<DT><B>also</B>
<DD>
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
<B>also</B>
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
<B>also</B>
parameter and an
<B>include</B>
line.
(Caution, see BUGS below for some restrictions.)
<DT><B>alsoflip</B>
<DD>
can be used in a
<B>conn</B>
section.
It acts like an
<B>also</B>
that flips the referenced section's entries left-for-right.
</DL>
<P>
Parameter names beginning with
<B>x-</B>
(or
<B>X-</B>,
or
<B>x_</B>,
or
<B>X_</B>)
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.
<P>
A section with name
<B>%default</B>
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
<B>%default</B>
section.
There may be multiple
<B>%default</B>
sections of a given type,
but only one default may be supplied for any specific parameter name,
and all
<B>%default</B>
sections of a given type must precede all non-<B>%default</B>
sections of that type.
<B>%default</B>
sections may not contain
<B>also</B>
or
<B>alsoflip</B>
parameters.
<P>
Currently there are two types of section:
a
<B>config</B>
section specifies general configuration information for IPsec,
while a
<B>conn</B>
section specifies an IPsec connection.
<A NAME="lbAD">&nbsp;</A>
<H2>CONN SECTIONS</H2>
A
<B>conn</B>
section contains a
<I>connection specification</I>,
defining a network connection to be made using IPsec.
The name given is arbitrary, and is used to identify the connection to
<I><A HREF="ipsec_auto.8.html">ipsec_auto</A></I>(8)
and
<I><A HREF="ipsec_manual.8.html">ipsec_manual</A></I>(8).
Here's a simple example:
<P>
<PRE>
<B>
conn snt
left=10.11.11.1
leftsubnet=10.0.1.0/24
leftnexthop=172.16.55.66
right=192.168.22.1
rightsubnet=10.0.2.0/24
rightnexthop=172.16.88.99
keyingtries=%forever
</B></PRE>
<P>
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''.
<P>
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
<I>left</I>
and
<I>right</I>
participants,
rather than in terms of local and remote.
Which participant is considered
<I>left</I>
or
<I>right</I>
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
<I>left</I>
for the local side and
<I>right</I>
for the remote side (the first letters are a good mnemonic).
<P>
Many of the parameters relate to one participant or the other;
only the ones for
<I>left</I>
are listed here, but every parameter whose name begins with
<B>left</B>
has a
<B>right</B>
counterpart,
whose description is the same but with
<B>left</B>
and
<B>right</B>
reversed.
<P>
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.
<A NAME="lbAE">&nbsp;</A>
<H3>CONN PARAMETERS: GENERAL</H3>
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.
<DL COMPACT>
<DT><B>type</B>
<DD>
the type of the connection; currently the accepted values
are
<B>tunnel</B>
(the default)
signifying a host-to-host, host-to-subnet, or subnet-to-subnet tunnel;
<B>transport</B>,
signifying host-to-host transport mode;
<B>passthrough</B>,
signifying that no IPsec processing should be done at all;
<B>drop</B>,
signifying that packets should be discarded; and
<B>reject</B>,
signifying that packets should be discarded and a diagnostic ICMP returned.
<DT><B>left</B>
<DD>
(required)
the IP address of the left participant's public-network interface,
in any form accepted by
<I><A HREF="ipsec_ttoaddr.3.html">ipsec_ttoaddr</A></I>(3)
or one of several magic values.
If it is
<B>%defaultroute</B>,
and
the
<B>config</B>
<B>setup</B>
section's,
<B>interfaces</B>
specification contains
<B>%defaultroute,</B>
<B>left</B>
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
<B>leftnexthop</B>.
(Either
<B>left</B>
or
<B>right</B>
may be
<B>%defaultroute</B>,
but not both.)
The value
<B>%any</B>
signifies an address to be filled in (by automatic keying) during
negotiation.
The value
<B>%opportunistic</B>
signifies that both
<B>left</B>
and
<B>leftnexthop</B>
are to be filled in (by automatic keying) from DNS data for
<B>left</B>'s
client.
The values
<B>%group</B>
and
<B>%opportunisticgroup</B>
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.
<DT><B>leftsubnet</B>
<DD>
private subnet behind the left participant, expressed as
<I>network</I><B>/</B><I>netmask</I>
(actually, any form acceptable to
<I><A HREF="ipsec_ttosubnet.3.html">ipsec_ttosubnet</A></I>(3));
if omitted, essentially assumed to be <I>left</I><B>/32</B>,
signifying that the left end of the connection goes to the left participant only
<DT><B>leftnexthop</B>
<DD>
next-hop gateway IP address for the left participant's connection
to the public network;
defaults to
<B>%direct</B>
(meaning
<I>right</I>).
If the value is to be overridden by the
<B>left=%defaultroute</B>
method (see above),
an explicit value must
<I>not</I>
be given.
If that method is not being used,
but
<B>leftnexthop</B>
is
<B>%defaultroute</B>,
and
<B>interfaces=%defaultroute</B>
is used in the
<B>config</B>
<B>setup</B>
section,
the next-hop gateway address of the default-route interface
will be used.
The magic value
<B>%direct</B>
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.
<DT><B>leftupdown</B>
<DD>
what ``updown'' script to run to adjust routing and/or firewalling
when the status of the connection
changes (default
<B>ipsec _updown</B>).
May include positional parameters separated by white space
(although this requires enclosing the whole string in quotes);
including shell metacharacters is unwise.
See
<I><A HREF="ipsec_pluto.8.html">ipsec_pluto</A></I>(8)
for details.
Relevant only locally, other end need not agree on it.
<DT><B>leftfirewall</B>
<DD>
whether the left participant is doing forwarding-firewalling
(including masquerading) for traffic from <I>leftsubnet</I>,
which should be turned off (for traffic to the other subnet)
once the connection is established;
acceptable values are
<B>yes</B>
and (the default)
<B>no</B>.
May not be used in the same connection description with
<B>leftupdown</B>.
Implemented as a parameter to the default
<I>updown</I>
script.
See notes below.
Relevant only locally, other end need not agree on it.
</DL>
<P>
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
<I>updown</I>
script (see
<I><A HREF="ipsec_pluto.8.html">ipsec_pluto</A></I>(8)).
<P>
The implementation of this makes certain assumptions about firewall setup,
notably the use of the old
<I>ipfwadm</I>
interface to the firewall.
In situations calling for more control,
it may be preferable for the user to supply his own
<I>updown</I>
script,
which makes the appropriate adjustments for his system.
<A NAME="lbAF">&nbsp;</A>
<H3>CONN PARAMETERS: AUTOMATIC KEYING</H3>
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.
<DL COMPACT>
<DT><B>keyexchange</B>
<DD>
method of key exchange;
the default and currently the only accepted value is
<B>ike</B>
<DT><B>auto</B>
<DD>
what operation, if any, should be done automatically at IPsec startup;
currently-accepted values are
<B>add</B>
(signifying an
<B>ipsec auto</B>
<B>--add</B>),
<B>route</B>
(signifying that plus an
<B>ipsec auto</B>
<B>--route</B>),
<B>start</B>
(signifying that plus an
<B>ipsec auto</B>
<B>--up</B>),
<B>manual</B>
(signifying an
<B>ipsec</B>
<B>manual</B>
<B>--up</B>),
and
<B>ignore</B>
(also the default) (signifying no automatic startup operation).
See the
<B>config</B>
<B>setup</B>
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
<B>auto=start</B>
to ensure that any reboot causes immediate renegotiation).
<DT><B>auth</B>
<DD>
whether authentication should be done as part of
ESP encryption, or separately using the AH protocol;
acceptable values are
<B>esp</B>
(the default) and
<B>ah</B>.
<DT><B>authby</B>
<DD>
how the two security gateways should authenticate each other;
acceptable values are
<B>secret</B>
for shared secrets,
<B>rsasig</B>
for RSA digital signatures (the default),
<B>secret|rsasig</B>
for either, and
<B>never</B>
if negotiation is never to be attempted or accepted (useful for shunt-only conns).
Digital signatures are superior in every way to shared secrets.
<DT><B>leftid</B>
<DD>
how
the left participant
should be identified for authentication;
defaults to
<B>left</B>.
Can be an IP address (in any
<I><A HREF="ipsec_ttoaddr.3.html">ipsec_ttoaddr</A></I>(3)
syntax)
or a fully-qualified domain name preceded by
<B>@</B>
(which is used as a literal string and not resolved).
The magic value
<B>%myid</B>
stands for the current setting of <I>myid</I>.
This is set in <B>config setup</B> or by <I><A HREF="ipsec_whack.8.html">ipsec_whack</A></I>(8)), or, if not set,
it is the IP address in <B>%defaultroute</B> (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.
<DT><B>leftrsasigkey</B>
<DD>
the left participant's
public key for RSA signature authentication,
in RFC 2537 format using
<I><A HREF="ipsec_ttodata.3.html">ipsec_ttodata</A></I>(3)
encoding.
The magic value
<B>%none</B>
means the same as not specifying a value (useful to override a default).
The value
<B>%dnsondemand</B>
(the default)
means the key is to be fetched from DNS at the time it is needed.
The value
<B>%dnsonload</B>
means the key is to be fetched from DNS at the time
the connection description is read from
<I>ipsec.conf</I>;
currently this will be treated as
<B>%none</B>
if
<B>right=%any</B>
or
<B>right=%opportunistic</B>.
The value
<B>%dns</B>
is currently treated as
<B>%dnsonload</B>
but will change to
<B>%dnsondemand</B>
in the future.
The identity used for the left participant
must be a specific host, not
<B>%any</B>
or another magic value.
<B>Caution:</B>
if two connection descriptions
specify different public keys for the same
<B>leftid</B>,
confusion and madness will ensue.
<DT><B>leftrsasigkey2</B>
<DD>
if present, a second public key.
Either key can authenticate the signature, allowing for key rollover.
<DT><B>pfs</B>
<DD>
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);
acceptable values are
<B>yes</B>
(the default)
and
<B>no</B>.
<DT><B>keylife</B>
<DD>
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
<B>s</B>
(a time in seconds)
or a decimal number followed by
<B>m</B>,
<B>h</B>,
or
<B>d</B>
(a time
in minutes, hours, or days respectively)
(default
<B>8.0h</B>,
maximum
<B>24h</B>).
Normally, the connection is renegotiated (via the keying channel)
before it expires.
The two ends need not exactly agree on
<B>keylife</B>,
although if they do not,
there will be some clutter of superseded connections on the end
which thinks the lifetime is longer.
<DT><B>rekey</B>
<DD>
whether a connection should be renegotiated when it is about to expire;
acceptable values are
<B>yes</B>
(the default)
and
<B>no</B>.
The two ends need not agree,
but while a value of
<B>no</B>
prevents Pluto from requesting renegotiation,
it does not prevent responding to renegotiation requested from the other end,
so
<B>no</B>
will be largely ineffective unless both ends agree on it.
<DT><B>rekeymargin</B>
<DD>
how long before connection expiry or keying-channel expiry
should attempts to
negotiate a replacement
begin; acceptable values as for
<B>keylife</B>
(default
<B>9m</B>).
Relevant only locally, other end need not agree on it.
<DT><B>rekeyfuzz</B>
<DD>
maximum percentage by which
<B>rekeymargin</B>
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
<I><A HREF="ipsec_pluto.8.html">ipsec_pluto</A></I>(8),
currently
<B>100%</B>).
The value of
<B>rekeymargin</B>,
after this random increase,
must not exceed
<B>keylife</B>.
The value
<B>0%</B>
will suppress time randomization.
Relevant only locally, other end need not agree on it.
<DT><B>keyingtries</B>
<DD>
how many attempts (a whole number or <B>%forever</B>) should be made to
negotiate a connection, or a replacement for one, before giving up
(default
<B>%forever</B>).
The value <B>%forever</B>
means ``never give up'' (obsolete: this can be written <B>0</B>).
Relevant only locally, other end need not agree on it.
<DT><B>ikelifetime</B>
<DD>
how long the keying channel of a connection (buzzphrase: ``ISAKMP SA'')
should last before being renegotiated;
acceptable values as for
<B>keylife</B>
(default set by
<I><A HREF="ipsec_pluto.8.html">ipsec_pluto</A></I>(8),
currently
<B>1h</B>,
maximum
<B>8h</B>).
The two-ends-disagree case is similar to that of
<B>keylife</B>.
<DT><B>compress</B>
<DD>
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 <I>before</I> encryption);
acceptable values are
<B>yes</B>
and
<B>no</B>
(the default).
The two ends need not agree.
A value of
<B>yes</B>
causes IPsec to propose both compressed and uncompressed,
and prefer compressed.
A value of
<B>no</B>
prevents IPsec from proposing compression;
a proposal to compress will still be accepted.
<DT><B>disablearrivalcheck</B>
<DD>
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
<B>yes</B>
and
<B>no</B>
(the default).
Tunnel-exit checks improve security and do not break any normal configuration.
Relevant only locally, other end need not agree on it.
<DT><B>failureshunt</B>
<DD>
what to do with packets when negotiation fails.
The default is
<B>none</B>:
no shunt;
<B>passthrough</B>,
<B>drop</B>,
and
<B>reject</B>
have the obvious meanings.
</DL>
<A NAME="lbAG">&nbsp;</A>
<H3>CONN PARAMETERS: MANUAL KEYING</H3>
The following parameters are relevant only to manual keying,
and are ignored in automatic 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.
A manually-keyed
connection must specify at least one of AH or ESP.
<DL COMPACT>
<DT><B>spi</B>
<DD>
(this or
<B>spibase</B>
required for manual keying)
the SPI number to be used for the connection (see
<I><A HREF="ipsec_manual.8.html">ipsec_manual</A></I>(8));
must be of the form <B>0x</B><I>hex</I><B></B>,
where
<I>hex</I>
is one or more hexadecimal digits
(note, it will generally be necessary to make
<I>spi</I>
at least
<B>0x100</B>
to be acceptable to KLIPS,
and use of SPIs in the range
<B>0x100</B>-<B>0xfff</B>
is recommended)
<DT><B>spibase</B>
<DD>
(this or
<B>spi</B>
required for manual keying)
the base number for the SPIs to be used for the connection (see
<I><A HREF="ipsec_manual.8.html">ipsec_manual</A></I>(8));
must be of the form <B>0x</B><I>hex</I><B>0</B>,
where
<I>hex</I>
is one or more hexadecimal digits
(note, it will generally be necessary to make
<I>spibase</I>
at least
<B>0x100</B>
for the resulting SPIs
to be acceptable to KLIPS,
and use of numbers in the range
<B>0x100</B>-<B>0xff0</B>
is recommended)
<DT><B>esp</B>
<DD>
ESP encryption/authentication algorithm to be used
for the connection, e.g.
<B>3des-md5-96</B>
(must be suitable as a value of
<I><A HREF="ipsec_spi.8.html">ipsec_spi</A></I>(8)'s
<B>--esp</B>
option);
default is not to use ESP
<DT><B>espenckey</B>
<DD>
ESP encryption key
(must be suitable as a value of
<I><A HREF="ipsec_spi.8.html">ipsec_spi</A></I>(8)'s
<B>--enckey</B>
option)
(may be specified separately for each direction using
<B>leftespenckey</B>
(leftward SA)
and
<B>rightespenckey</B>
parameters)
<DT><B>espauthkey</B>
<DD>
ESP authentication key
(must be suitable as a value of
<I><A HREF="ipsec_spi.8.html">ipsec_spi</A></I>(8)'s
<B>--authkey</B>
option)
(may be specified separately for each direction using
<B>leftespauthkey</B>
(leftward SA)
and
<B>rightespauthkey</B>
parameters)
<DT><B>espreplay_window</B>
<DD>
ESP replay-window setting,
an integer from
<B>0</B>
(the
<I>ipsec_manual</I>
default, which turns off replay protection) to
<B>64</B>;
relevant only if ESP authentication is being used
<DT><B>leftespspi</B>
<DD>
SPI to be used for the leftward ESP SA, overriding
automatic assignment using
<B>spi</B>
or
<B>spibase</B>;
typically a hexadecimal number beginning with
<B>0x</B>
<DT><B>ah</B>
<DD>
AH authentication algorithm to be used
for the connection, e.g.
<B>hmac-md5-96</B>
(must be suitable as a value of
<I><A HREF="ipsec_spi.8.html">ipsec_spi</A></I>(8)'s
<B>--ah</B>
option);
default is not to use AH
<DT><B>ahkey</B>
<DD>
(required if
<B>ah</B>
is present) AH authentication key
(must be suitable as a value of
<I><A HREF="ipsec_spi.8.html">ipsec_spi</A></I>(8)'s
<B>--authkey</B>
option)
(may be specified separately for each direction using
<B>leftahkey</B>
(leftward SA)
and
<B>rightahkey</B>
parameters)
<DT><B>ahreplay_window</B>
<DD>
AH replay-window setting,
an integer from
<B>0</B>
(the
<I>ipsec_manual</I>
default, which turns off replay protection) to
<B>64</B>
<DT><B>leftahspi</B>
<DD>
SPI to be used for the leftward AH SA, overriding
automatic assignment using
<B>spi</B>
or
<B>spibase</B>;
typically a hexadecimal number beginning with
<B>0x</B>
</DL>
<A NAME="lbAH">&nbsp;</A>
<H2>CONFIG SECTIONS</H2>
At present, the only
<B>config</B>
section known to the IPsec software is the one named
<B>setup</B>,
which contains information used when the software is being started
(see
<I><A HREF="ipsec_setup.8.html">ipsec_setup</A></I>(8)).
Here's an example:
<P>
<PRE>
<B>
config setup
interfaces=&quot;ipsec0=eth1 ipsec1=ppp0&quot;
klipsdebug=none
plutodebug=all
manualstart=
</B></PRE>
<P>
Parameters are optional unless marked ``(required)''.
The currently-accepted
<I>parameter</I>
names in a
<B>config</B>
<B>setup</B>
section are:
<DL COMPACT>
<DT><B>myid</B>
<DD>
the identity to be used for
<B>%myid</B>.
<B>%myid</B>
is used in the implicit policy group conns and can be used as
an identity in explicit conns.
If unspecified,
<B>%myid</B>
is set to the IP address in <B>%defaultroute</B> (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 ``<B>@</B>''.
<DT><B>interfaces</B>
<DD>
virtual and physical interfaces for IPsec to use:
a single
<I>virtual</I><B>=</B><I>physical</I> pair, a (quoted!) list of pairs separated
by white space, or
<B>%none</B>.
One of the pairs may be written as
<B>%defaultroute</B>,
which means: find the interface <I>d</I> that the default route points to,
and then act as if the value was ``<B>ipsec0=</B><I>d</I>''.
<B>%defaultroute</B>
is the default;
<B>%none</B>
must be used to denote no interfaces.
If
<B>%defaultroute</B>
is used (implicitly or explicitly)
information about the default route and its interface is noted for
use by
<I><A HREF="ipsec_manual.8.html">ipsec_manual</A></I>(8)
and
<I><A HREF="ipsec_auto.8.html">ipsec_auto</A></I>(8).)
<DT><B>forwardcontrol</B>
<DD>
whether
<I>setup</I>
should turn IP forwarding on
(if it's not already on) as IPsec is started,
and turn it off again (if it was off) as IPsec is stopped;
acceptable values are
<B>yes</B>
and (the default)
<B>no</B>.
For this to have full effect, forwarding must be
disabled before the hardware interfaces are brought
up (e.g.,
<B>net.ipv4.ip_forward&nbsp;=&nbsp;0</B>
in Red Hat 6.x
<I>/etc/sysctl.conf</I>),
because IPsec doesn't get control early enough to do that.
<DT><B>rp_filter</B>
<DD>
whether and how
<I>setup</I>
should adjust the reverse path filtering mechanism for the
physical devices to be used.
Values are <B>%unchanged</B> (to leave it alone)
or <B>0</B>, <B>1</B>, <B>2</B> (values to set it to).
<I>/proc/sys/net/ipv4/conf/PHYS/rp_filter</I>
is badly documented; it must be <B>0</B> in many cases
for ipsec to function.
The default value for the parameter is <B>0</B>.
<DT><B>syslog</B>
<DD>
the
<I><A HREF="syslog.2.html">syslog</A></I>(2)
``facility'' name and priority to use for
startup/shutdown log messages,
default
<B>daemon.error</B>.
<DT><B>klipsdebug</B>
<DD>
how much KLIPS debugging output should be logged.
An empty value,
or the magic value
<B>none</B>,
means no debugging output (the default).
The magic value
<B>all</B>
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
<I><A HREF="ipsec_klipsdebug.8.html">ipsec_klipsdebug</A></I>(8).
<DT><B>plutodebug</B>
<DD>
how much Pluto debugging output should be logged.
An empty value,
or the magic value
<B>none</B>,
means no debugging output (the default).
The magic value
<B>all</B>
means full output.
Otherwise only the specified types of output
(a quoted list, names without the
<B>--debug-</B>
prefix,
separated by white space) are enabled;
for details on available debugging types, see
<I><A HREF="ipsec_pluto.8.html">ipsec_pluto</A></I>(8).
<DT><B>plutoopts</B>
<DD>
additional options to pass to pluto upon startup. See
<I><A HREF="ipsec_pluto.8.html">ipsec_pluto</A></I>(8).
<DT><B>plutostderrlog</B>
<DD>
do not use syslog, but rather log to stderr, and direct stderr to the
argument file.
<DT><B>dumpdir</B>
<DD>
in what directory should things started by
<I>setup</I>
(notably the Pluto daemon) be allowed to
dump core?
The empty value (the default) means they are not
allowed to.
<DT><B>manualstart</B>
<DD>
which manually-keyed connections to set up at startup
(empty, a name, or a quoted list of names separated by white space);
see
<I><A HREF="ipsec_manual.8.html">ipsec_manual</A></I>(8).
Default is none.
<DT><B>pluto</B>
<DD>
whether to start Pluto or not;
Values are
<B>yes</B>
(the default)
or
<B>no</B>
(useful only in special circumstances).
<DT><B>plutowait</B>
<DD>
should Pluto wait for each
negotiation attempt that is part of startup to
finish before proceeding with the next?
Values are
<B>yes</B>
or
<B>no</B>
(the default).
<DT><B>prepluto</B>
<DD>
shell command to run before starting Pluto
(e.g., to decrypt an encrypted copy of the
<I>ipsec.secrets</I>
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
<I>/dev/tty</I>
or equivalent for their interaction.
Default is none.
<DT><B>postpluto</B>
<DD>
shell command to run after starting Pluto
(e.g., to remove a decrypted copy of the
<I>ipsec.secrets</I>
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
<I>/dev/tty</I>
or equivalent for their interaction.
Default is none.
<DT><B>fragicmp</B>
<DD>
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
<B>yes</B>
(the default)
and
<B>no</B>.
<DT><B>hidetos</B>
<DD>
whether a tunnel packet's TOS field should be set to
<B>0</B>
rather than copied from the user packet inside;
acceptable values are
<B>yes</B>
(the default)
and
<B>no</B>.
<DT><B>uniqueids</B>
<DD>
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
<B>yes</B>
(the default)
and
<B>no</B>.
Participant IDs normally <I>are</I> unique,
so a new (automatically-keyed) connection using the same ID is
almost invariably intended to replace an old one.
<DT><B>overridemtu</B>
<DD>
value that the MTU of the ipsec<I>n</I> interface(s) should be set to,
overriding IPsec's (large) default.
This parameter is needed only in special situations.
</DL>
<A NAME="lbAI">&nbsp;</A>
<H2>IMPLICIT CONNS</H2>
<P>
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 <B>auto=ignore</B>,
the definition is suppressed.
<P>
Here are the automatically supplied definitions.
<P>
<PRE>
<B>
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
keylife=1h
rekey=no
auto=route
conn private-or-clear
type=tunnel
left=%defaultroute
leftid=%myid
right=%opportunisticgroup
failureshunt=passthrough
keyingtries=3
ikelifetime=1h
keylife=1h
rekey=no
auto=route
conn private
type=tunnel
left=%defaultroute
leftid=%myid
right=%opportunisticgroup
failureshunt=drop
keyingtries=3
ikelifetime=1h
keylife=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
keylife=1h
rekey=no
auto=route
</B></PRE>
<P>
These conns are <I>not</I> affected by anything in <B>conn %default</B>.
They will only work if <B>%defaultroute</B> works.
The <B>leftid</B> will be the interfaces IP address; this
requires that reverse DNS records be set up properly.
<P>
The implicit conns are defined after all others. It is
appropriate and reasonable to use <B>also=private-or-clear</B>
(for example) in any other opportunistic conn.
<A NAME="lbAJ">&nbsp;</A>
<H2>POLICY GROUP FILES</H2>
<P>
The optional files under
<I>/etc/ipsec.d/policy</I>,
including
<PRE>
/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
</PRE>
may contain policy group configuration information to
supplement
<I>ipsec.conf</I>.
Their contents are not security-sensitive.
<P>
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.
<P>
A connection in
<I>/etc/ipsec.conf</I>
which has
<B>right=%group</B>
or
<B>right=%opportunisticgroup</B>
is a policy group connection.
When a policy group file of the same name is loaded, with
<P>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<B>ipsec auto --rereadgroups</B>
<P>
or at system start, the connection is instantiated such that each
CIDR block serves as an instance's
<B>right</B>
value. The system treats the
resulting instances as normal connections.
<P>
For example, given a suitable connection definition
<B>private</B>,
and the file
<I>/etc/ipsec.d/policy/private </I>
with an entry 192.0.2.3,
the system creates a connection instance
<B>private#192.0.2.3.</B>
This connection inherits all details from
<B>private</B>,
except that its right client is 192.0.2.3.
<A NAME="lbAK">&nbsp;</A>
<H2>DEFAULT POLICY GROUPS</H2>
<P>
The standard FreeS/WAN install includes several policy groups
which provide a way of classifying possible peers into IPsec security classes:
<B>private</B>
(talk encrypted only),
<B>private-or-clear</B>
(prefer encryption),
<B>clear-or-private</B>
(respond to requests for encryption),
<B>clear</B>
and
<B>block</B>.
Implicit policy groups apply to the local host only,
and are implemented by the
<B>IMPLICIT CONNECTIONS </B>
described above.
<A NAME="lbAL">&nbsp;</A>
<H2>CHOOSING A CONNECTION</H2>
<P>
When choosing a connection to apply to an outbound packet caught with a
<B>%trap,</B>
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.
<P>
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 -&gt; /32, but
for earlier stages of the negotiation, there will not be enough
information about the client subnets to complete the instantiation.
<A NAME="lbAM">&nbsp;</A>
<H2>FILES</H2>
<PRE>
/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
</PRE>
<A NAME="lbAN">&nbsp;</A>
<H2>SEE ALSO</H2>
<A HREF="ipsec.8.html">ipsec</A>(8), <A HREF="ipsec_ttoaddr.8.html">ipsec_ttoaddr</A>(8), <A HREF="ipsec_auto.8.html">ipsec_auto</A>(8), <A HREF="ipsec_manual.8.html">ipsec_manual</A>(8), <A HREF="ipsec_rsasigkey.8.html">ipsec_rsasigkey</A>(8)
<A NAME="lbAO">&nbsp;</A>
<H2>HISTORY</H2>
Designed for the FreeS/WAN project
&lt;<A HREF="http://www.freeswan.org">http://www.freeswan.org</A>&gt;
by Henry Spencer.
<A NAME="lbAP">&nbsp;</A>
<H2>BUGS</H2>
<P>
When
<B>type</B>
or
<B>failureshunt</B>
is set to
<B>drop</B>
or
<B>reject,</B>
FreeS/WAN blocks outbound packets using eroutes, but assumes inbound
blocking is handled by the firewall. FreeS/WAN offers firewall hooks
via an ``updown'' script. However, the default
<B>ipsec _updown</B>
provides no help in controlling a modern firewall.
<P>
Including attributes of the keying channel
(authentication methods,
<B>ikelifetime</B>,
etc.)
as an attribute of a connection,
rather than of a participant pair, is dubious and incurs limitations.
<P>
<I>Ipsec_manual</I>
is not nearly as generous about the syntax of subnets,
addresses, etc. as the usual FreeS/WAN user interfaces.
Four-component dotted-decimal must be used for all addresses.
It
<I>is</I>
smart enough to translate bit-count netmasks to dotted-decimal form.
<P>
It would be good to have a line-continuation syntax,
especially for the very long lines involved in
RSA signature keys.
<P>
The ability to specify different identities,
<B>authby</B>,
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
<B>0.0.0.0</B>,
and that is considered to be the ``participant'' for such connections.
<P>
In principle it might be necessary to control MTU on an
interface-by-interface basis,
rather than with the single global override that
<B>overridemtu</B>
provides.
<P>
A number of features which <I>could</I> 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.
<P>
If conns are to be added before DNS is available,
<B>left=</B><I>FQDN</I>,
<B>leftnextop=</B><I>FQDN</I>,
and
<B>leftrsasigkey=%dnsonload</B>
will fail.
<I><A HREF="ipsec_pluto.8.html">ipsec_pluto</A></I>(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).
<P>
The <B>myid</B> option does not affect explicit <B> ipsec auto --add</B> or <B>ipsec auto --replace</B> commands for implicit conns.
<P>
<HR>
<A NAME="index">&nbsp;</A><H2>Index</H2>
<DL>
<DT><A HREF="#lbAB">NAME</A><DD>
<DT><A HREF="#lbAC">DESCRIPTION</A><DD>
<DT><A HREF="#lbAD">CONN SECTIONS</A><DD>
<DL>
<DT><A HREF="#lbAE">CONN PARAMETERS: GENERAL</A><DD>
<DT><A HREF="#lbAF">CONN PARAMETERS: AUTOMATIC KEYING</A><DD>
<DT><A HREF="#lbAG">CONN PARAMETERS: MANUAL KEYING</A><DD>
</DL>
<DT><A HREF="#lbAH">CONFIG SECTIONS</A><DD>
<DT><A HREF="#lbAI">IMPLICIT CONNS</A><DD>
<DT><A HREF="#lbAJ">POLICY GROUP FILES</A><DD>
<DT><A HREF="#lbAK">DEFAULT POLICY GROUPS</A><DD>
<DT><A HREF="#lbAL">CHOOSING A CONNECTION</A><DD>
<DT><A HREF="#lbAM">FILES</A><DD>
<DT><A HREF="#lbAN">SEE ALSO</A><DD>
<DT><A HREF="#lbAO">HISTORY</A><DD>
<DT><A HREF="#lbAP">BUGS</A><DD>
</DL>
<HR>
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using the manual pages.<BR>
Time: 21:40:17 GMT, November 11, 2003
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