DVMRPD(8)               OpenBSD System Manager's Manual              DVMRPD(8)

NAME
     dvmrpd - Distance Vector Multicast Routing Protocol daemon

SYNOPSIS
     dvmrpd [-dnv] [-f file]

DESCRIPTION
     dvmrpd is the Distance Vector Multicast Routing Protocol (DVMRP) daemon,
     which manages multicast routing tables.  This implementation supports
     DVMRP version 3.255, thus it is only capable of maintaining IPv4 multi-
     cast routing tables.

     DVMRP uses a distance vector routing algorithm to build reverse path mul-
     ticast delivery trees.  A flood and prune approach is used to determine
     which branches in the network have multicast listeners.  The usual draw-
     backs of a distance vector route protocol applies to DVMRP: slow conver-
     gence and scalability issues.

     DVMRP routers communicate via the multicast group 224.0.0.4 All DVMRP
     Routers.  IP protocol number 2 (IGMP) is used, furthermore DVMRP packets
     omit the use of TCP and UDP.

     It is possible to interconnect multicast networks with the use of tun-
     nels.  Tunnels can traverse routers and networks not supporting multi-
     cast.  dvmrpd does not support tunneling as described in RFC 1075, since
     it has been abandoned.  dvmrpd can tunnel multicast traffic using generic
     solutions such as gre(4).

     DVMRP is used for handling multicast routing exclusively.  It is not re-
     quired that a unicast routing protocol is used in conjunction with DVMRP.

     dvmrpd is usually started at boot time, and can be enabled by setting the
     following in /etc/rc.conf.local:

           dvmrpd_flags=""

     See rc(8) and rc.conf(8) for more information on the boot process and en-
     abling daemons.

     A running dvmrpd can be controlled with the dvmrpctl(8) utility.

     The options are as follows:

     -d      Do not daemonize.  If this option is specified, dvmrpd will run
             in the foreground and log to stderr.

     -f file
             Specify an alternative configuration file.

     -n      Configtest mode.  Only check the configuration file for validity.

     -v      Produce more verbose output.

FILES
     /etc/dvmrpd.conf        Default dvmrpd configuration file.
     /var/run/dvmrpd.sock    UNIX-domain socket used for communication with
                             dvmrpctl(8).

SEE ALSO
     dvmrpd.conf(5), dvmrpctl(8)

     DVMRP Version 3, draft-ietf-idmr-dvmrp-v3-11, August 2000.

HISTORY
     The dvmrpd program first appeared in OpenBSD 4.0.

OpenBSD 4.7                    October 22, 2009                              2
