dhcp relay questions..

Simon Hobson dhcp1 at thehobsons.co.uk
Tue Jul 18 07:07:23 UTC 2006

foomail123 wrote:

>1) For DHCP relay - where do I find documentation,
>how to configure, debug etc. (from developer point
>of view) ?

Starting point would be "man dhrelay"

>2)  Does dhcp relay maintain state of each request/
>response between server and client ? If so, is there
>tool to dump dhcp relay database ?

No, DHCP Relay is a stateless function.

>3) Is relay a independent daemon ? Any dependency on
>server code or runtime ?

It's a standalone package, it does not even have to be run on a 
routing machine. It also is not dependant on having a particular 
vendors DHCP Server.

>4) what are steps to run dhcp relay ?

Check the man page.

 From memory (of reading this list, I don't use dhrelay myself), you 
would want (where is the dhcp server) :



dhrelay -i eth0 -i eth1 1234

to use only specific interfaces.

A quirk of the way implementation was done is that you must tell the 
relay to listen not only on the client facing interface, but also on 
the interface that replies from the server will come from. If you are 
running the relay on some machine on the clients subnet (not a 
router) then these are both the same interface, but if the machine is 
also the router they will be different. Also related to this quirk is 
that the connection towards the server cannot be a PPP interface.


More information about the dhcp-users mailing list