— Distance Vector Multicast
Routing Protocol daemon
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
multicast routing tables.
DVMRP uses a distance vector routing algorithm to build reverse path multicast
delivery trees. A flood and prune approach is used to determine which branches
in the network have multicast listeners. The usual drawbacks of a distance
vector route protocol applies to DVMRP: slow convergence and scalability
DVMRP routers communicate via the multicast group 188.8.131.52 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 tunnels.
Tunnels can traverse routers and networks not supporting multicast.
does not support tunneling as described in RFC 1075,
since it has been abandoned. dvmrpd
can tunnel multicast
traffic using generic solutions such as
DVMRP is used for handling multicast routing exclusively. It is not required
that a unicast routing protocol is used in conjunction with DVMRP.
is usually started at boot time, and can be enabled by
setting the following in /etc/rc.conf.local
for more information on the
boot process and enabling daemons.
A running dvmrpd
can be controlled with the
The options are as follows:
- Do not daemonize. If this option is specified,
dvmrpd will run in the foreground and log to
- Specify an alternative configuration file.
- Configtest mode. Only check the configuration file for
- Produce more verbose output.
- Default dvmrpd configuration file.
- UNIX-domain socket used for
communication with dvmrpctl(8).
DVMRP Version 3,
program first appeared in OpenBSD