IP helper-address command

misthe · 01-31-2008, 02:47 PM

Well the problem is that the command doesn't work when i use it on a router which is on a different , subnet from the router which is attached on my switch.
I applied the command ip helper-address on the fastethernet interface of my router which in turn must sent it to another dhcp router and doesn't work.
Any ideas...

ARC1450 · 01-31-2008, 03:20 PM

Could you clarify?

You have two routers connected, and you can't get a DHCP broadcast to traverse both of them? Is that what you're saying? If that's the case, both routers have to be RFC compliant for forwarding DHCP requests across them.

farslayer · 01-31-2008, 03:27 PM

DHCP Server Address 192.168.1.10

The address used for the command ip helper-address is the address of the DHCP SERVER not the IP of the next router in line..

Code:

DHCPD-192.168.1.10-----192.168.1.1-e0-R1-e1-192.168.2.1--------192.168.2.2-e0-R2-e1-192.168.3.1---------192.168.3.2-e0-R3-e1-192.168.4.1-----

So the ip helper-address command for interface e1 would be the same for ALL of these routers.. R1, R2, and R3

interface ethernet 1
ip helper-address 192.168.1.10

So what are you doing differently ?