Problem when multiple dhcrelay instances relay to a common server

[mark mckinstry]

On our system (Linux-based) we are running an instance of dhcrelay for
each client interface, so that relay configuration (e.g. -m option) can
be different for each client, and so that requests from each client can
optionally be relayed to a different server.


This seems to work OK as long as each relay instance is configured with
a different server address, but whenever they have a common server
address the relay starts relaying multiple duplicate packets to the
server for each client request. We get around 10 such duplicate packets
per request when there are two dhcrelay instances running, and 100 when
there's three instances running.


Can anyone shed some light on what might be going on here?


Thanks
Mark