Subject: Multicasting problem
To: None <>
From: Andreas Oman <>
List: tech-net
Date: 09/17/2001 18:03:54
Hi, i have a question regarding multicast routing

The kernel does not send a packet to a multicast destination
if it does not exist in the routingtable even though i've specified
an explicit interface with IP_MUlTICAST_IF with setsockopt().

It is not possible to bypass by setting the SO_DONTROUTE flag either.

Am I required to install a route to pointing to some dummy
destiation ? (and a default route is out of the question)

Is this behaviour intentional ?

Or have i missed something when setting up the socket ?

Personally i'd like to see routing to be 100% bypassed if an interface has
been explicit specified for a socket.

Best regards /Andreas