[Xorp-users] IGMP report group ...?

[Hervé Léonard]

Hi,

In fact, i do some other tests...

The flag 'ALLMULTI' for the network card driver (in ifconfig) was not the
root cause of the group membership in xorp router.

It was in fact the IGMP version number for the interface in Xorp
configuration.

With the IGMP version 2 (by default) the IGMP membership doesn't work. But
with version 3, it does.

I thought that only one router on the LAN can send IGMP Query, it is the
Querier IGMP. And this Querier IGMP should deal with 3 versions of IGMP for
all different kinds of hosts on the LAN...

Is that the case with Xorp?

Thanks,

Leonard



-----Message d'origine-----
De : Bruce M Simpson
Envoyé : lundi 6 octobre 2008 17:46
À : Hervé Léonard
Cc : xorp-users at xorp.org
Objet : Re: [Xorp-users] IGMP report group ...?


Hervé Léonard wrote:
> Hi,
>
> I try to join a group multicast by sending a IGMP report message from a
> Linux host to a Linux Xorp router (both on a Linux 2.6 - Ubuntu 8.04 Hardy
> Heron)
> ...
> Host A tries to join the group 239.7.7.7 or 224.7.7.7 by sending IGMP
report
> v2 on the LAN. Xorp Router B do nothing...?
>
..

It looks like your XORP router has not received any IGMPv2 JOIN messages.

Please do the following:

1. Check that your network card driver supports "multicast promiscuous"
mode (aka ALLMULTI).
   ifconfig should tell you if this bit is set.

2. Check that your router is receiving the IGMPv2 JOIN messages on the
correct MAC address, by passing the -e switch to tcpdump. For IGMPv2,
this should be the same as the group's MAC address itself.

We need to be sure that the IGMP messages are in fact being accepted by
the socket layer, and going to the xorp_fea process. Most likely the
problem is further down in the stack though, I've had problems with the
FreeBSD fxp(4) driver recently.

thanks
BMS

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