ip helper-address in or out of a vrf

ropakalns · ‎09-16-2010

Hi!

I have a question regarding 6509 config:

interface Vlan33
ip vrf forwarding old_lan
ip address 10.4.2.1 255.255.255.0
ip helper-address 10.10.1.2
end

Should I configure the ip helper-address in a vrf or will it understand that the helper must look for the dhcp server in the vrf "old_lan"? I don't have an option to configure ip helper-address vrf xxx.

Best regards,

Roberts

Atif Awan · ‎09-22-2010

ropakalns wrote:

Hi!

I have a question regarding 6509 config:

interface Vlan33
ip vrf forwarding old_lan
ip address 10.4.2.1 255.255.255.0
ip helper-address 10.10.1.2
end

Should I configure the ip helper-address in a vrf or will it understand that the helper must look for the dhcp server in the vrf "old_lan"? I don't have an option to configure ip helper-address vrf xxx.

Best regards,

Roberts

VRF-aware DHCP relay has been supported for quite sometime now. If your only requirement is to relay DHCP requests to a DHCP server within the VRF old_lan then you are ok with using the ip helper-address statement under the interface that is part of the VRF without using the VRF keyword. The vrf keyword is for 'VRF aware DHCP' feature which is not currently supported and is probably not what you need anyway.

Atif

ropakalns · ‎09-23-2010

Hi Atif!

Thank's for your reply!

Turns out that 6k supports only ip-helper in global table. I opened a TAC case and they told me that this won't work (server is in the old_lan vrf). So seems that with catalyst it requests the IP on the global routing table. I know that in a router configuration it would ask for an IP in the vrf, but this config has a different logic. So I need to find a workaround here...

Roberts

Atif Awan · ‎09-23-2010

I am a bit confused here as to what you are trying to achieve. If the only requirement is to have devices part of the VRF be assigned an IP-Address by a DHCP server dedicated for this VRF and reachable within the VRF then this works with the configuration you have. Do you have a more elaborate requirement? Are you expecting to use a Central DHCP Server for all VRFs?

Atif