ISAKMPD(8) BSD System Manager's Manual ISAKMPD(8)
isakmpd - ISAKMP/Oakley a.k.a. IKE key management daemon
isakmpd [-46adKLnTv] [-c config-file] [-D class=level] [-f fifo] [-i pid-file] [-l packetlog-file] [-N udpencap-port] [-p listen- port] [-R report-file]
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 confi- guration 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 ini- tiations from a remote party, user input via a FIFO or by signals, up- calls 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 net- works" (VPNs). 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 the 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(8) or by other programs like bgpd(8). Thus isakmpd only takes care of the SA es- tablishment. -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 run- ning the daemon. isakmpd will reread the configuration file when sent a SIGHUP signal. -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 de- bugging 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. -d The -d option is used to make the daemon run in the foreground, logging to stderr. -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. Note that only paths beginning with /var/run are allowed. -K When this option is given, isakmpd does not read the policy con- figuration file and no keynote(4) policy check is accomplished. This option can be used when policies for flows and SA establish- ment 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 pack- ets 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. -N udpencap-port The -N option specifies the listen port for encapsulated UDP that the daemon will bind to. -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. -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. Note that only paths beginning with /var/run are al- lowed. -T When this option is given, NAT-Traversal will be disabled and isakmpd will not advertise support for NAT-Traversal to its peers. -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 in- formation).
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 add [section]:tag=value C rm [section]:tag C rms [section] C set [section]:tag=value C set [section]:tag=value force Update the running isakmpd configuration atomically. 'set' sets a configuration value consisting of a section, tag, and value tri- plet. '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 con- figuration list tag. 'rm' removes a tag in a section. 'rms' re- moves 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. c <name> Start the named connection, if stopped or inactive. 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. d <cookies> <msgid> Delete the specified SA from the system. Specify <msgid> as '-' to match a Phase 1 SA. 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 Reinitialize isakmpd, as when sent a SIGHUP signal. r Report isakmpd internal state to a file. See the -R option. Same as when sent a SIGUSR1 signal. S Report information on all known SAs to the /var/run/isakmpd.result file. T Tear down all active connections. t <name> Tear down the named connection, if active. SETTING UP AN IKE PUBLIC KEY INFRASTRUCTURE (PKI) In order to use public key based authentication, there has to be an in- frastructure managing the key signing. Either there is an already exist- ing PKI isakmpd should take part in, or there will be a need to set one up. The procedures for using a pre-existing PKI varies depending on the actual Certificate Authority (CA) used, and is therefore not covered here, other than mentioning that openssl(1) needs to be used to create a Certificate Signing Request (CSR) that the CA understands. A number of methods exist to allow authentication: Passphrase: This method does not use keys at all, but relies on a shared passphrase. See vpn(8) for an example implementation. Host Keys: Public keys are used to authenticate. See PUBLIC KEY AUTHENTICATION below. X509 Certificates: X509 Certificates are used to authenticate. See X509 AUTHENTICATION below. Keynote Certificates: Keynote Certificates are used to authenticate. See KEYNOTE AUTHENTICATION below.
It is possible to store trusted public keys to make them directly usable by isakmpd, bypassing the need to use certificates. 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 By default, the system startup script rc(8) generates a key-pair when starting, if one does not already exist. The private and public keys are named local.key and local.pub, respectively. Depending on the ID-type field of isakmpd.conf(5), keys may be named after their IPv4 address (IPV4_ADDR or IPV4_ADDR_SUBNET), IPv6 address (IPV6_ADDR or IPV6_ADDR_SUBNET), fully qualified domain name (FDQN), user fully quali- fied domain name (USER_FQDN), or key ID (KEY_ID). For example, isakmpd can authenticate using the pre-generated keys if the local public key is copied to the remote gateway as /etc/isakmpd/pubkeys/ipv4/local.gateway.ip.address and the remote gateway's public key is copied to the local gateway as /etc/isakmpd/pubkeys/ipv4/remote.gateway.ip.address. Of course, new keys may also be generated (the user is not required to use the pre-generated keys). In this example, ID-type would also have to be set to IPV4_ADDR or IPV4_ADDR_SUBNET in isakmpd.conf(5).
X509 is a framework for public key certificates. Certificates can be gen- erated using openssl(1) and provide a means for PKI authentication. In the following example, a CA is created along with host certificates to be signed by the CA. 1. Create your own Certificate Authority (CA). Create a self-signed root certificate. The CA certificate is named ca.crt, and its private key ca.key: # openssl req -x509 -days 365 -newkey rsa:1024 \ -keyout /etc/ssl/private/ca.key \ -out /etc/ssl/ca.crt openssl req will prompt for information that will be incorporated into the certificate request. The information entered comprises a Distinguished Name (DN). There are quite a few fields, but some can be left blank. For some fields there will be a default value; if '.' is entered, the field will be left blank. 2. Create Certificate Signing Requests (CSRs) for IKE peers. The CSRs are signed with a pre-generated private key. By default, the system startup script rc(8) generates a key-pair when starting, if one does not already exist. The private and public keys are named local.key and local.pub, respectively. 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 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 as below. A subjectAltName extension field should be added to the certificate. This field is not mandatory, but is highly recom- mended since it allows isakmpd to avoid "man in the middle" attacks. Replace 10.0.0.1 with the IP address which isakmpd will use as the certificate identity. # 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 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.
Keynote is a trust-management framework. Keys can be generated using keynote(1) and provide an alternative means for isakmpd to authenticate. See keynote(4) for further information.
/etc/isakmpd/ca/ The directory where CA certificates are kept. /etc/isakmpd/certs/ The directory where IKE certificates are kept, 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 are kept. /etc/isakmpd/isakmpd.conf The configuration file. As this file can contain sensitive infor- mation 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/keynote/ The directory where KeyNote credentials are kept. /etc/isakmpd/private/ The directory where local private keys for certificate-based au- thentication, and their public key counterparts, are kept. By de- fault, the system startup script rc(8) generates a key-pair when starting, if one does not already exist. The private and public keys are named local.key and local.pub, respectively. There has to be a certificate for local.key in the certificate directory, /etc/isakmpd/certs/. local.key has the same mode requirements as isakmpd.conf. /etc/isakmpd/pubkeys/ The directory in which trusted public keys are kept. The keys must be named in the fashion described above. /usr/share/ipsec/isakmpd/ A directory containing some sample isakmpd and keynote policy configuration files. /var/run/isakmpd.fifo The FIFO used to manually control isakmpd. /var/run/isakmpd.pcap The default IKE packet capture file. /var/run/isakmpd.pid The PID of the current daemon. /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.
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 RFC 2407, RFC 2408, and RFC 2409. NAT-Traversal is described in RFC 3947. This imple- mentation 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 pro- cess 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. MirOS BSD #10-current August 07, 2002 5
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