DHCP Relay over transit-network

Simon Hobson simon at thehobsons.co.uk
Tue Dec 30 13:13:49 UTC 2014

"Muenz, Michael" <m.muenz at spam-fetish.org> wrote:

> Ok, got some news. Clients sending normal DHCP Inform's receive replies, but DHCP Discover messages won't get replied.

DHCP Inform will be unicast directly from the client to the server - so the relay agent isn't involved.

> With wireshark on the external IF of FW1 ( I can see "Relay agent IP address:", so the internal IP for FW1 which is correct, but I can't find a GI-Addr field.

Same thing, different names.
Check on FW2 that the packets are going through, and whether there is any reply at all from the server. Then look at the server logs.
And assuming FW2 isn't the default gateway for the server at that end, check that the server (or the default router) has a route to the transit network.

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