Comware

we have several vlans routed on a procurve 9300 core switch using udp helper addresses configured for each client vlan.

a client sends out a dhcp request that is forwarded via subnet directed broadcast (that is udp helper address 1.2.3.255 as an example). The client receives offers from all relevant dhcp servers but one. We are using Enteo as a RIS server that is configured to answer dhcp requests. It will offer no IP addresses but only the required boot image information.

The Enteo server receives the dhcp request from the client and sends out the offer with ip address 0.0.0.0 and the boot filename as an dhcp option. Apparently the udp helper on the 9300 core switch does not forward the offer to the requesting dhcp client.

Any ideas?

Hi, maboko4711 !

At the first step a dhcp client uses a broadcast sending request to a dhcp server.
Afterwards both dhcp server and client use unicasts communicating with each other.
0.0.0.0 means an unknown address.
To be able to communicate with the dhcp server and to accept the dhcp offer the client should have a KNOWN ip address distinct from 0.0.0.0.
If the client and server reside in different ip networks (within different vlans) both should know the routes to each other.

Good luck,
Dmitry

Add a extra iphelper to your pxe server. That should do the trick.

That means one Iphelper forwarding to your dhcp server and one to your pxe per vlan.