Centos 6.3 Server ignoring IGMP Queries

StackOverflow https://stackoverflow.com/questions/15786048

  •  31-03-2022
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Question

I am using a centos 6.3 server to subscribe to UDP multicast data and I noticed that my server doesn't answer to the IGMP queries sent by the switch it is connected to.

As a result, when I open my multicast socket I start receiving multicast data until my IGMP subscription timeout since the server doesn't renew its subscription. (To insure that the problem doesn't comes from any code of mine, I am simply using smcroute to open multicast subscriptions)

I search online for a while and none of the tips I found helped me to fix this problem.

Here is an screenshot of the IGMP communications on any interface of my server:

http://img521.imageshack.us/img521/9953/capture10y.png

As we can see, my server first send 2 IGMP joins but a few minutes after, when the switch send IGMP query, nobody answers.

The version of the IGMP protocol set for the concerned interface is V2:

[root@localhost ~]# cat /proc/net/igmp
Idx Device    : Count Querier   Group    Users Timer    Reporter
1   lo        :     0      V2
                010000E0     1 0:00000000       0
2   eth0      :     5      V2
                FB0000E0     1 0:00000000       1
                010000E0     1 0:00000000       0
5   tap0      :     5      V3
                FB0000E0     1 0:00000000       0
                010000E0     1 0:00000000       0
7   eth1.371:    13      V2
            414000E0     1 0:00000000       1
            404000E0     1 0:00000000       1
            3F4000E0     1 0:00000000       1
            504000E0     1 0:00000000       1
            524000E0     1 0:00000000       1
            494000E0     1 0:00000000       1
            4A4000E0     1 0:00000000       1
            4B4000E0     1 0:00000000       1
            FB0000E0     1 0:00000000       0
            010000E0     1 0:00000000       0

The rp_filter is disabled on this interface:

[root@localhost ~]# cat /proc/sys/net/ipv4/conf/eth1.371/rp_filter 
0

Thanks a lot for any help you could give me.

Best,

Laurent

Was it helpful?

Solution 2

It might be coming from asymmetric route rules. DO you have a rule to reach 170.19.52.5 from your server? (you can use route -n)

OTHER TIPS

Try to temporary disable iptables:

# service iptables stop

and see if it will help.

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