Forwarding DHCP Requests through HP 2650, 25214 and 4000 switches

[Lenny Davis]

I am about to setup some VLANs on our LAN as we are running out of IP addresses in our 192.168.50.0/24 address range and I need to know how to obtain DHCP addresses for PC's on a new VLAN 192.168.51.0 from a DHCP server on the 192.168.50.0 network.  The PC's on the 192.168.51.0 NW will be connected to either HP procurve 2650 and 2524 switches and an old Procurve 4000 switch.  These Procurves are connected to ports in the new 192.168.51.0 VLAN on a Cisco 3750 stack, on which the DHCP server is directly connected in the existing 192.168.50.0 network.

I see something called ip-helper mentioned sevrla times but this appears to be applicable to Cisco routers / switches and not HP procurves?

Any advice would be greatly appreciated.

Thanks

Lenny

[paulgear]

The equivalent command on ProCurve switches is 'ip helper-address'. I can't remember if it is present on 2524 or 4000 switches - check the manual to be sure.

[paulgear · Accepted solution]

P.S. The ip helper-address command is used at the VLAN interface context. So you need to have an IP address set up on the switch on each of the relevant VLANs in order to get it going.

But you don't necessarily need to do it this way - you could instead do the VLANning on the Cisco and put all of the DHCP forwarding smarts there. Then you would not need to do any VLANning on the ProCurves. It's up to you - either way would work.

[Lenny Davis]

Thanks for that info.  Yes I found out the ip helper-address command isn't present on the 2524 switches but yes I need to implement it on the Cisco switches and not the HP Procurves as you have suggested.

Cheers

Lenny