This site best when viewed with a modern standards-compliant browser. We recommend Firefox Get Firefox!.

Linux-HA project logo
Providing Open Source High-Availability Software for Linux and other OSes since 1999.

USA Flag UK Flag

Japanese Flag


About Us

Contact Us

Legal Info

How To Contribute

Security Issues

This web page is no longer maintained. Information presented here exists only to avoid breaking historical links.
The Project stays maintained, and lives on: see the Linux-HA Reference Documentation.
To get rid of this notice, you may want to browse the old wiki instead.

1 February 2010 Hearbeat 3.0.2 released see the Release Notes

18 January 2009 Pacemaker 1.0.7 released see the Release Notes

16 November 2009 LINBIT new Heartbeat Steward see the Announcement

Last site update:
2021-10-22 06:27:46

mcast - configures multicast communication path

The mcast directive is used to configure a multicast communication path.

The syntax of an mcast directive is:

mcast dev mcast-group udp-port ttl 0
  • dev - IP device to send/rcv heartbeats on

  • mcast-group - multicast group to join (class D multicast address - For most Heartbeat uses, the first byte should be 239.

  • port - UDP port to sendto/rcvfrom (set this to the same value as udpport)

  • ttl - the ttl value for outbound heartbeats. This affects how far the multicast packet will propagate. (0-255). Set to 1 for the current subnet. Must be greater than zero.

A sample mcast directive is shown below:

mcast eth0 694 1 0


This directive has a few more parameters than it should.

See Also

Wikipedia, The TCP/IP guide