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I have upgraded a server from RH4 -> RH5.5 and we have an interesting issue with multicast.

  • we have multiple NICS on the server, we want the bond0 to default as the default interface.
  • adding route dev bond0 doesn't seem to work.
  • removing multicast from the other interfaces via ifconfig -multicast does not work either.
  • as you can see below, eth0 seems to be the default interface.
  • everything works fine if I down the interfaces in front of bond0 first.
    $ ip route dev eth0  proto kernel  scope link  src dev eth5  proto kernel  scope link  src dev bond1  proto kernel  scope link  src dev bond0  proto kernel  scope link  src dev eth6  proto kernel  scope link  src dev eth6  scope link
    ** dev bond0  scope link**
    default via dev bond0

    $ netstat -g
    IPv6/IPv4 Group Memberships
    Interface       RefCnt Group
    --------------- ------ ---------------------
    lo              1      ALL-SYSTEMS.MCAST.NET
    eth0            1
    eth0            1
    **eth0            1      ALL-SYSTEMS.MCAST.NET**
    eth5            1      ALL-SYSTEMS.MCAST.NET
    eth6            1      ALL-SYSTEMS.MCAST.NET
    bond0           1      ALL-SYSTEMS.MCAST.NET
    bond1           1      ALL-SYSTEMS.MCAST.NET

    $ tcpdump -i eth0
    tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
    listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes
    00:18:58.093483 IP > UDP, length 24
    00:18:58.231905 IP > PIM-ROUTERS.MCAST.NET: PIMv2, Hello, length: 34
    00:18:58.492444 IP > UDP, length 24
    00:18:58.851423 IP > UDP, length 24
    00:18:58.891409 IP > UDP, length 24
    00:18:58.902533 IP > UDP, length 161
    00:18:59.040125 802.1d unknown version
    00:18:59.291385 IP > UDP, length 24
    00:18:59.690362 IP > UDP, length 24
    00:18:59.851356 IP > UDP, length 24
    00:18:59.851716 IP > UDP, length 45
    00:18:59.904441 IP > UDP, length 161
    00:19:00.105330 IP > UDP, length 24
    00:19:00.221321 IP > igmp v2 report
    00:19:00.504310 IP > UDP, length 24
share|improve this question
This is when you ask RedHat support, it may have been a regression with the particular kernel release installed. – Steve-o Aug 24 '11 at 9:25

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