Multicast over GRE between Linux server and Cisco Router

Brian Christopher Raaen mailing-lists at
Wed Jan 9 15:51:33 UTC 2013

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

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