Understanding dhcrelay

[Paul]

Kay Wanous wrote:
> Hello,
>
> I'm trying to set up dhcrelay but based on what I'm reading I think 
> I'm either missing a critical step or I don't understand how it works.
>
> The dhcrelay server receives a DHCP request on its internal interface 
> (192.168.0.1) and places that IP address in the giaddr field, then 
> sends it from its outside interface (routable IP) to the dhcp server 
> (routable IP).  The dhcp server sees the giaddr and instead of 
> replying to the routable IP of the dhcrelay server, it responds to 
> 192.168.0.1.  But since the dhcp server can't reach the internal 
> network, the response is never received on the dhcrelay server.
>
> Since the dhcp server can't get to the internal network (isn't that 
> the whole idea of dhcrelay?), if it's answering to the giaddr field, 
> how would the response ever get back to the dhcrelay server so that it 
> could get back to the requesting client?
>
> Any help in clearing up this confusion is greatly appreciated.
>
> Thanks,
> Kay
>
I don't understand why you would want a DCHP server on a routable 
network to be providing IP addresses on a non-routable network, but if I 
had to configure it I would have the DHCP replying to the routable 
address of the dhcp relay server, otherwise it would never receive 
anything to relay to the non-routable machine. The problem I have 
understanding this is, if the machine is non-routable/non-reachable, of 
what use would a (routable) IP address be to it?

Cheers,


-- 


Paul Blonde
EnTel Communications Inc
Ph: 250-633-5151
TF: 866-633-2644
Fx: 250-633-2677