multiple dhcp relay configuration

Simon Hobson dhcp1 at thehobsons.co.uk
Tue Nov 7 14:03:51 UTC 2006


<tajinder.pal at wipro.com> wrote:
>  sorry gif could not be send, I think it is filtered by mailing list.

Yes, attachments are removed.


>Vintcert(192.168.0.1: eth1)    dhcp server
>	^
>    	|
>	|
>Hamming (192.168.0.2: eth1; 192.168.1.1 eth2)
>	^
>	|
>	|
>Dijkstra (192.168.1.2: eth2; 192.168.2.1: eth0)  "dhcrelay 192.168.0.1"
>	^
>	|
>	|
>Nyquist ( dhcp : eth0)     dhcp client
>
>
>I can ping from eth1/vintcerf to eth2/dijkstra and vice-versa.

Can you ping from vintcerf to eth0 on dijkstra (192.168.2.1) ?

If not then you have a routing problem


Do you have any filtering anywhere ? If so, does it permit dhcp traffic ?


If you put a client (with fixed address) on client subnet, can it 
communicate with vintcerf ?


When you have eliminated all the above potential problems, then it's 
time to look at the dhcp config.


If you put a client on 192.168.0.x subnet, does it get a lease - or 
if you don't have a range for that subnet, does the server log 'no 
free leases' ?

Do you have a subnet declaration for 192.168.2.x and an available 
range within it ?


If you are still having trouble, then I suggest using a packet 
sniffer (I use ethereal/tethereal) to sniff for packets at various 
points. Does the client send out a dhcp discover broadcast ? Does 
dijkstra forward it (via unicast) to vintcerf ? Does vintcerf send 
back any reply ? does it appear on the wire at the client end ?




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