ISAKMPD(8)

NAME
isakmpd - ISAKMP/Oakley a.k.a. IKE key management daemon

SYNOPSIS
isakmpd [-c config-file] [-d] [-D class=level] [-f fifo] [-i pid-file] [-n] [-p listen-port] [-P local-port] [-L] [-l packetlog-file] [-r seed] [-R report-file]

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 triggers these negotiations. The events that control isakmpd consists 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 setup 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.

The options are as follows:

-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. This argument is possible to specify 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
    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 say, 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.

-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 receiveing. 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.

  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 setup one. In the former case, what is needed to be done varies depending on the actual Certificate Authority used, and is therefore not covered here, more 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 now being 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 or a 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 some extensions to the certificate in order to make it usable for isakmpd. There are two possible ways to add the extensions to the certificate. Either you have to 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

    (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/.

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

BUGS
The -P flag does not do what we document, rather it does nothing.

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.

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/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 after a 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_sa
    The report file written when the 'S' command is issued in the command FIFO.

/usr/share/ipsec/isakmpd/
    A directory containing some sample isakmpd and keynote policy configuration files.

SEE ALSO
ipsec(4), isakmpd.conf(5), isakmpd.policy(5), getnameinfo(3), openssl(1), pcap(3), photurisd(8), ssl(8), tcpdump(8), vpn(8)

HISTORY
The ISAKMP/Oakley key management protocol is described in the RFCs and This implementation was done 1998 by Niklas Hallqvist and Niels Provos, sponsored by Ericsson Radio Systems.