RIS Server not seeing other subnets

[psycho.chicken]

Our ris and dhcp server are on subnet 90

Clients are on 10, 20, 30 etc.

RIS and DHCP are on seperate boxes.

We'll call RIS 10.0.0.76
We'll call DHCP 10.0.0.72
Gateway is 10.0.0.100
Both on vlan 90

When clients try to get the RIS server, they get a DHCP address, but never get a reply from RIS.

If I set a client into vlan 90, and add 2 helper address' both for RIS and DHCP it works fine, doesnt work without the 2nd helper address...

I need RIS to work on other vlans...
I did enable proxy arp on vlan 90 and the client vlans, as well as the client vlan's

Please advise...

[Ron Kinner]

Interesting problem. I thought something was odd when you said you had to use ip helper addresses to make it work on VLAN90 but I found this on Microsoft's site:

"The RIS client disk always communicates through the default gateway (if the default gateway is configured) to connect to RIS. This occurs even if the RIS and DHCP server are on the same subnet that the computer is on."

http://support.microsoft.com/kb/255952



I suspect that the RIS client uses a directed-broadcast (eg 10.0.0.255 if the mask is 255.255.255.0) to reach the RIS and this is not routed by default in later versions of Cisco IOS. HP seems to use a very similar IOS so you might try adding the command

ip directed-broadcast

to the interfaces involved. Suspect that since you are not really going through the router when your client is connected on vlan 90 that it doesn't get blocked then and that the first ip helper address (for the RIS) is not needed.

If that's not it, then on Cisco routers ip helper-address only works for certain UDP ports and I think RIS uses UDP 4011 which is not on the list. Try adding the global config command

ip forward-protocol udp 4011

to the router.

Ron