ISAKMPD(8) BSD System Manager's Manual ISAKMPD(8)
isakmpd -- ISAKMP/Oakley a.k.a. IKE key management daemon
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]
The isakmpd daemon establishes security associations for encrypted and/or authenticated network traffic. At this moment, and probably for-
ever, 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 negotia-
tion 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 sched-
uled 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 pro-
grams like bgpd(8). Thus isakmpd only takes care of the SA establishment.
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.
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:
10 FIFO user interface
Currently used values for level are 0 to 99.
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.
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.
The -p option specifies the listen port the daemon will bind to.
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).
As option -L above, but capture to a specified file.
If given, a deterministic random number sequence will be used internally. This is useful for setting up regression tests.
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 log-
ging isakmpd reports successful completion of phase 1 (Main and Aggressive) and phase 2 (Quick) exchanges (Information and Transac-
tion 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
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
-extfile /etc/ssl/x509v3.cnf -extensions x509v3_CA
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 recom-
mended, as it should be unique.
# openssl genrsa -out /etc/isakmpd/private/local.key 1024
# openssl req -new -key /etc/isakmpd/private/local.key
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
# certpatch -i 10.0.0.1 -k /etc/ssl/private/ca.key
# 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
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
-extfile /etc/ssl/x509v3.cnf -extensions x509v3_FQDN
or with certpatch(8)
# certpatch -t fqdn -i somehost.somedomain
(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 /email@example.com
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:
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 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.
Tear down the named connection, if active.
T Tear down all active connections.
/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.
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.
openssl(1), getnameinfo(3), pcap(3), ipsec(4), isakmpd.conf(5), isakmpd.policy(5), ssl(8), tcpdump(8), vpn(8)
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.
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 lis-
tens on without a restart.
The -P flag does not do what we document, rather it does nothing.
BSD August 07, 2002 BSD