3524 Switch/DHCP Issue

[ntwrkrbkj]

Is there anyway to keep the 3524 from forwarding DHCP packets to a specific port? Specifically one of the GBIC uplinks without having to VLAN the traffic.

Thanks!

 

[burtsbees]

dhcp excluded addresses...is this a subnet directly connected to the GB interface?

Burt

 

[ntwrkrbkj]

Yeah, the problem is that this is a dissimilar network. We have a fiber connection over to another agency who has their own network. The connection is to allow us to share their T1 for a video conferencing.

We didn't have any issues until we promoted our server to a DC, now it's trying to be authoritatize over their DHCP servers.

 

[burtsbees]

Well, dhcp is a broadcast, so in order to cross a router/layer 3 switch to another network, it needs a dhcp helper command. Is there one in place? If not, dhcp broadcasts will not traverse into another network. Please describe the topology, and where the unwanted dhcp messages are coming from.

Burt

 

[ntwrkrbkj]

Wow, that was supposed to say *authoritative*, yikes what a typo.

Burt, trying to keep my dhcp packets from interferring with their servers, so I am actually trying to keep dhcp packets from going to their network. And I admit I am not learned enough to do it at layer 2, and there may be no way, I am not sure. The topology is as follows:

Our DHCP Server
|
Our 3524 Switch
GBIC - I want to kill DHCP across this link.
|
| Fiber Connection
|
GBIC
Their 3524 Switch
|
Their DHCP Server

Is it possible to do this without adding a router?

Thanks!

 

[brianinms]

There isn't a way to stop a broadcast from traversing a layer 2 network.

 

[burtsbees]

Correct---you will have to VLAN the traffic to prevent the broadcasts from interfering---it is never a good idea to have two dhcp servers on the same LAN segment. What kind of router is there? You could have the router (if it's a Cisco) do the dhcp for a certain scope, but not on the same LAN as another dhcp server.

Burt