SGE2010P DHCP Relay Problem

[DJX995]

I'll try to make this simple:

I setup my DHCP server in the switch then added the VLAN that I want to forward for.

Running Wireshark on my server:

I can see the DHCP Discover from the foreign VLAN coming from the swtich.

My DHCP server responds with a DHCP Offer back to the switch.

It stops there and keeps repeating the process.

SGE2010P Version 3.0.0.18

Layer 3 Mode

Windows Server 2008 DHCP Server

Any thoughts?

[DJX995]

Well, I got it to work, but I'm still not sure why...

I am running DHCP Snooping and apparently, I need the router interface to be in the trusted interfaces category.

My router is some how using ICMP to redirect from it's IP back to the server?

So it goes:

DHCP Discover from switch (with foreign host info) to server

DHCP Offer from server (with offer info) to switch

? Router to Server with redirect information via ICMP ?

DHCP Request from Switch to server

DHCP ACK from server to switch

I never set anything in the router to forward DHCP.

I'm not sure why the request is getting to the router or why it even needs the router.

Is it because the servers' gateway is actually the router, not the switch?

My understanding is that this all should work with just the switch.

[Jean-Pierre Burlet]

Hey,

what is your network and get the DHCP via a interface vlan...?

did you configure the helper address? (ip helper-address DHCP-Server)

Greetings

JP

[David Carr]

Hey FratianiD,

Based on what your stating the issue is because of the gateway being the router and not the Switch.  Since I don't have your network diagram, if you have multiple vlans accessing the server and the way to it is on a different gateway that will pose why it can't get to it.

Good information though. 

Thanks for posting your fix.