DHCP Snooping on L3 Switch

Starkiller08

Commendable
Oct 27, 2016
8
0
1,510
Hello friends,

The scenario is the next one:

I have a layer 3 switch (Cisco SG300-10MP) with and internal DHCP Server. It serves as an uplink for 3 layer 2 switches and have some endpoints connected to it.

There are no Vlans configurated and the DHCP server is working for everybody in the network.
I understand that when you activate DHCP snooping, you have to mark ports as trusted or non trusted if the DHCP server is in a dedicated server o router.

The question here is, How I have to configure the DHCP snooping in the L3 switch which have the DHCP server?

Do I have to internaly bridge the dhcp server to a port, and if so, how do I do that?
 
I have never tried this but my guess is all the ports are untrusted. What you are trying to prevent is dhcp offer messages coming in from a server.

This is a inbound traffic filter and since DHCP offers are only being sent outbound it should work.


Now DHCP snooping actually does a little more in that it prevents ip address spoofing also but that should not cause any issue either.