Provided by: isakmpd_20041012-10build1_amd64 
NAME
isakmpd — ISAKMP/Oakley a.k.a. IKE key management daemon
SYNOPSIS
isakmpd [-4] [-6] [-c config-file] [-a] [-d] [-D class=level] [-f fifo] [-i pid-file] [-n]
[-p listen-port] [-P local-port] [-K] [-L] [-l packetlog-file] [-r seed]
[-R report-file] [-v]
DESCRIPTION
The isakmpd daemon establishes security associations for encrypted and/or authenticated
network traffic. At this moment, and probably forever, this means ipsec(4) traffic.
The way isakmpd goes about its work is by maintaining an internal configuration as well as a
policy database which describes what kinds of SAs to negotiate, and by listening for
different events that trigger these negotiations. The events that control isakmpd consist
of negotiation initiations from a remote party, user input via a FIFO or by signals, upcalls
from the kernel via a PF_KEY socket, and lastly by scheduled events triggered by timers
running out.
Most uses of isakmpd will be to implement so called "virtual private networks" or VPNs for
short. The vpn(8) manual page describes how to set up isakmpd for a simple VPN. For other
uses, some more knowledge of IKE as a protocol is required. One source of information are
the RFCs mentioned below.
On startup isakmpd forks into two processes for privilege separation. The unprivileged
child jails itself with chroot(8) to /var/empty. The privileged process communicates with
the child, reads configuration files and PKI information and binds to privileged ports on
its behalf. See CAVEATS section below.
The options are as follows:
-4 | -6
These options control what address family (AF_INET and/or AF_INET6) isakmpd will
use. The default is to use both IPv4 and IPv6.
-a If given, isakmpd does not set up flows automatically. This is useful when flows
are configured with ipsecadm(4) or by other programs like bgpd(8). Thus isakmpd
only takes care of the SA establishment.
-c config-file
If given, the -c option specifies an alternate configuration file instead of
/etc/isakmpd/isakmpd.conf. As this file may contain sensitive information, it must
be readable only by the user running the daemon. isakmpd will reread the
configuration file when sent a SIGHUP signal.
-d The -d option is used to make the daemon run in the foreground, logging to stderr.
-D class=level
Debugging class. It's possible to specify this argument many times. It takes a
parameter of the form class=level, where both class and level are numbers. class
denotes a debugging class, and level the level you want that debugging class to
limit debug printouts at (i.e., all debug printouts above the level specified will
not output anything). If class is set to ‘A’, then all debugging classes are set to
the specified level.
Valid values for class are as follows:
0 Misc
1 Transport
2 Message
3 Crypto
4 Timer
5 Sysdep
6 SA
7 Exchange
8 Negotiation
9 Policy
10 FIFO user interface
A All
Currently used values for level are 0 to 99.
-f fifo
The -f option specifies the FIFO (a.k.a. named pipe) where the daemon listens for
user requests. If the path given is a dash (‘-’), isakmpd will listen to stdin
instead.
-i pid-file
By default the PID of the daemon process will be written to /var/run/isakmpd.pid.
This path can be overridden by specifying another one as the argument to the -i
option.
-n When the -n option is given, the kernel will not take part in the negotiations.
This is a non-destructive mode, so to speak, in that it won't alter any SAs in the
IPsec stack.
-p listen-port
The -p option specifies the listen port the daemon will bind to.
-P local-port
On the other hand, the port specified to capital -P will be what the daemon binds
its local end to when acting as initiator.
-K When this option is given, isakmpd does not read the policy configuration file and
no keynote(4) policy check is accomplished. This option can be used when policies
for flows and SA establishment are arranged by other programs like ipsecadm(8) or
bgpd(8).
-L Enable IKE packet capture. When this option is given, isakmpd will capture to file
an unencrypted copy of the negotiation packets it is sending and receiving. This
file can later be read by tcpdump(8) and other utilities using pcap(3).
-l packetlog-file
As option -L above, but capture to a specified file.
-r seed
If given, a deterministic random number sequence will be used internally. This is
useful for setting up regression tests.
-R report-file
When you signal isakmpd a SIGUSR1, it will report its internal state to a report
file, normally /var/run/isakmpd.report, but this can be changed by feeding the file
name as an argument to the -R flag.
-v Enables verbose logging. Normally, isakmpd is silent and outputs only messages when
a warning or an error occurs. With verbose logging isakmpd reports successful
completion of phase 1 (Main and Aggressive) and phase 2 (Quick) exchanges
(Information and Transaction exchanges do not generate any additional status
information).
Setting up an IKE public key infrastructure (a.k.a. PKI)
In order to use public key based authentication, there has to be an infrastructure managing
the key signing. Either there is an already existing PKI isakmpd should take part in, or
there will be a need to set one up. In the former case, what is needed to be done varies
depending on the actual Certificate Authority used, and is therefore not covered here, other
than mentioning that openssl(1) needs to be used to create a certificate signing request
that the CA understands. The latter case, however, is described here:
1. Create your own CA as root.
# openssl genrsa -out /etc/ssl/private/ca.key 1024
# openssl req -new -key /etc/ssl/private/ca.key \
-out /etc/ssl/private/ca.csr
You are then asked to enter information that will be incorporated into your certificate
request. What you are about to enter is what is called a Distinguished Name (DN).
There are quite a few fields but you can leave some blank. For some fields there will
be a default value; if you enter ‘.’, the field will be left blank.
# openssl x509 -req -days 365 -in /etc/ssl/private/ca.csr \
-signkey /etc/ssl/private/ca.key \
-extfile /etc/ssl/x509v3.cnf -extensions x509v3_CA \
-out /etc/ssl/ca.crt
2. Create keys and certificates for your IKE peers. This step as well as the next one,
needs to be done for every peer. Furthermore the last step will need to be done once
for each ID you want the peer to have. The 10.0.0.1 below symbolizes that ID, in this
case an IPv4 ID, and should be changed for each invocation. You will be asked for a DN
for each run. Encoding the ID in the common name is recommended, as it should be
unique.
# openssl genrsa -out /etc/isakmpd/private/local.key 1024
# openssl req -new -key /etc/isakmpd/private/local.key \
-out /etc/isakmpd/private/10.0.0.1.csr
Now take these certificate signing requests to your CA and process them like below.
You have to add a subjectAltName extension field to the certificate in order to make it
usable by isakmpd. There are two possible ways to add the extensions to the
certificate. Either you have to run certpatch(8) or you have to make use of an OpenSSL
configuration file, for example /etc/ssl/x509v3.cnf. Replace 10.0.0.1 with the IP-
address which isakmpd will use as the certificate identity.
To use certpatch(8), do the following
# openssl x509 -req -days 365 -in 10.0.0.1.csr -CA /etc/ssl/ca.crt \
-CAkey /etc/ssl/private/ca.key -CAcreateserial \
-out 10.0.0.1.crt
# certpatch -i 10.0.0.1 -k /etc/ssl/private/ca.key \
10.0.0.1.crt 10.0.0.1.crt
Otherwise do
# setenv CERTIP 10.0.0.1
# openssl x509 -req -days 365 -in 10.0.0.1.csr -CA /etc/ssl/ca.crt \
-CAkey /etc/ssl/private/ca.key -CAcreateserial \
-extfile /etc/ssl/x509v3.cnf -extensions x509v3_IPAddr \
-out 10.0.0.1.crt
For a FQDN certificate, do
# setenv CERTFQDN somehost.somedomain
# openssl x509 -req -days 365 -in somehost.somedomain.csr \
-CA /etc/ssl/ca.crt -CAkey /etc/ssl/private/ca.key \
-CAcreateserial \
-extfile /etc/ssl/x509v3.cnf -extensions x509v3_FQDN \
-out somehost.somedomain.crt
or with certpatch(8)
# certpatch -t fqdn -i somehost.somedomain \
-k /etc/ssl/private/ca.key \
somehost.somedomain.crt somehost.somedomain.crt
(This assumes the previous steps were used to create a request for somehost.somedomain
instead of 10.0.0.1)
Put the certificate (the file ending in .crt) in /etc/isakmpd/certs/ on your local
system. Also carry over the CA cert /etc/ssl/ca.crt and put it in /etc/isakmpd/ca/.
To revoke certificates, create a Certificate Revocation List (CRL) file and install it in
the /etc/isakmpd/crls/ directory. See openssl(1) and the ‘crl’ subcommand for more info.
It is also possible to store trusted public keys to make them directly usable by isakmpd.
The keys should be saved in PEM format (see openssl(1)) and named and stored after this easy
formula:
For IPv4 identities /etc/isakmpd/pubkeys/ipv4/A.B.C.D
For IPv6 identities /etc/isakmpd/pubkeys/ipv6/abcd:abcd::ab:bc
For FQDN identities /etc/isakmpd/pubkeys/fqdn/foo.bar.org
For UFQDN identities /etc/isakmpd/pubkeys/ufqdn/user@foo.bar.org
The FIFO user interface
When isakmpd starts, it creates a FIFO (named pipe) where it listens for user requests. All
commands start with a single letter, followed by command-specific options. Available
commands are:
c <name>
Start the named connection, if stopped or inactive.
C set [section]:tag=value
C set [section]:tag=value force
C add [section]:tag=value
C rm [section]:tag
C rms [section]
Update the running isakmpd configuration atomically. ‘set’ sets a configuration
value consisting of a section, tag and value triplet. ‘set’ will fail if the
configuration already contains a section with the named tag; use the ‘force’ option
to change this behaviour. ‘add’ appends a configuration value to the named
configuration list tag. ‘rm’ removes a tag in a section. ‘rms’ removes an entire
section.
NOTE: Sending isakmpd a SIGHUP or an "R" through the FIFO will void any updates done
to the configuration.
C get [section]:tag
Get the configuration value of the specified section and tag. The result is stored
in /var/run/isakmpd.result.
d <cookies> <msgid>
Delete the specified SA from the system. Specify <msgid> as "-" to match a Phase 1
SA.
D <class> <level>
D A <level>
D T Set debug class <class> to level <level>. If <class> is specified as "A", the level
applies to all debug classes. "D T" toggles all debug classes to level zero.
Another "D T" command will toggle them back to the earlier levels.
p on[=<path>]
p off Enable or disable cleartext IKE packet capture. When enabling, optionally specify
which file isakmpd should capture the packets to.
Q Cleanly shutdown the daemon, as when sent a SIGTERM signal.
r Report isakmpd internal state to a file. See -R option. Same as when sent a
SIGUSR1 signal.
R Reinitialize isakmpd, as when sent a SIGHUP signal.
S Report information on all known SAs to the /var/run/isakmpd.result file.
t <name>
Tear down the named connection, if active.
T Tear down all active connections.
FILES
/etc/isakmpd/ca/ The directory where CA certificates can be found.
/etc/isakmpd/certs/ The directory where IKE certificates can be found, both the
local certificate(s) and those of the peers, if a choice to
have them kept permanently has been made.
/etc/isakmpd/crls/ The directory where CRLs can be found.
/etc/isakmpd/isakmpd.conf The configuration file. As this file can contain sensitive
information it must not be readable by anyone but the user
running isakmpd.
/etc/isakmpd/isakmpd.policy The keynote policy configuration file. The same mode
requirements as isakmpd.conf.
/etc/isakmpd/private/local.key
A local private key for certificate based authentication.
There has to be a certificate for this key in the certificate
directory mentioned above. The same mode requirements as
isakmpd.conf.
/etc/isakmpd/pubkeys/ Directory in which trusted public keys can be kept. The keys
must be named in the fashion described above.
/var/run/isakmpd.pid The PID of the current daemon.
/var/run/isakmpd.fifo The FIFO used to manually control isakmpd.
/var/run/isakmpd.pcap The default IKE packet capture file.
/var/run/isakmpd.report The report file written when SIGUSR1 is received.
/var/run/isakmpd.result The report file written when the ‘S’ or ‘C get’ command is
issued in the command FIFO.
/usr/share/ipsec/isakmpd/ A directory containing some sample isakmpd and keynote policy
configuration files.
SEE ALSO
openssl(1), getnameinfo(3), pcap(3), ipsec(4), isakmpd.conf(5), isakmpd.policy(5), ssl(8),
tcpdump(8), vpn(8)
HISTORY
The ISAKMP/Oakley key management protocol is described in the RFCs RFC 2407, RFC 2408 and
RFC 2409. This implementation was done 1998 by Niklas Hallqvist and Niels Provos, sponsored
by Ericsson Radio Systems.
CAVEATS
When storing a trusted public key for an IPv6 identity, the most efficient form of address
representation, i.e "::" instead of ":0:0:0:", must be used or the matching will fail.
isakmpd uses the output from getnameinfo(3) for the address-to-name translation. The
privileged process only allows binding to the default port 500 or unprivileged ports
(>1024). It is not possible to change the interfaces isakmpd listens on without a restart.
BUGS
The -P flag does not do what we document, rather it does nothing.