DHCP server failover behind relay

Alex Bligh alex at alex.org.uk
Thu Sep 6 21:47:00 UTC 2012

--On 6 September 2012 23:12:11 +0300 Vadym Abramchuk <abramm at gmail.com> 

> Just tried -j TEE and got the local loop with two servers copying packets
> to each other :(.
> Any idea on how to avoid this? TTL check looks weird.

Set two servers up each with a loopback address of W.X.Y.Z. Use that
address in the relay agents, and for dhcp to listen on. When you do
the -j TEE, also set some other marker on the packet (I'd suggest the
tos field - see --tos and --set-tos) to prevent looping.

Alex Bligh

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