conntrackd won't start, "can't open multicast server!"

[Max Kellermann <max@duempel.org>]

Hi Pablo,

I am currently working on the official conntrack-tools 0.9.5 Debian
package; I have been maintaining the old "conntrack" program before.
The daemon will not start (with examples/stats/conntrackd.conf):

 host:~# /usr/sbin/conntrackd -C /etc/conntrackd.conf 
 Notice: StripNAT clause is obsolete. Please, remove it from conntrackd.conf
 ERROR: conntrackd cannot start, please check the logfile for more info
 host:~# tail /var/log/conntrackd.log 
 [Fri Jan  4 09:01:25 2008] (pid=9353) --- starting in console mode ---
 [Fri Jan  4 09:01:25 2008] (pid=9353) [FAIL] can't open multicast server!
 [Fri Jan  4 09:01:25 2008] (pid=9353) [FAIL] initialization failed

This machine has CONFIG_IP_MULTICAST=y, although I do not understand
why conntrackd needs a multicast socket in the stats mode.  strace
says:

 socket(PF_UNSPEC, SOCK_DGRAM, 0) = -1 EAFNOSUPPORT (Address family
 not supported by protocol)

Also, the example shipped in the 0.9.5 includes the obsolete
"StripNAT" option.

Max