Ip helper on switch or DHCP relay on ASA??

[okoye11]

So we have taken over a network where they are using both DHCP Relay on their Cisco ASA and IP helper on the switch. We removed DHCP relay from the ASA but now it looks like only VLAN 1 is getting an up from dhcp. After adding it back in, it’s not working anymore. IP helper was not removed from the switch.

My question is do you guys prefer using dhcp relay on the firewall or using IP helper on the switch behind it??

[MHM Cisco World]

this depend on is ASA or SVI of SW is GW for client ??

[Richard Burts]

I agree with MHM that the answer to your question depends on things in your environment that we do not know, particularly where does layer 3 forwarding/routing take place. I can say that in general I believe that it is better if layer 3 forwarding/routing takes place before traffic gets to the ASA (let the ASA focus on security aspects of the traffic and have routing done by other devices). Based on that in general I would prefer switch helper address to ASA DHCP relay.