Multicast over GRE between Linux server and Cisco Router

Brian Christopher Raaen mailing-lists at
Fri Jan 11 12:11:37 UTC 2013

Just a quick note. I do have multicast enabled on the server gre1
interface.  A tshark capture shows the igmp group queries from the router
and the igmp join reply from the server.

On Wed, Jan 9, 2013 at 10:51 AM, Brian Christopher Raaen <
mailing-lists at> wrote:

> I am trying to set up multicast between a Linux server and Router using
> GRE.  The GRE tunnel is up fine and I can see traffic go across it, but the
> router is not indicating it is receiving the IGMP joins that the server is
> sending.  I have identical setting with another server attached to
> fastethernet0/1 and it is joined to the group fine, but I am not able to
> get the server to link to the router via GRE interface.  Note that I have
> another server behind another router where the two routers do GRE and PIM
> and that on is working fine.  Is there some reason that IGMP joins would
> not work across the GRE link, but another router using PIM would?
> --
> Brian Christopher Raaen
> Network Architect
> Zcorum

Brian Christopher Raaen
Network Architect

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