DHCP not leasing for certain modems.

Simon Hobson dhcp1 at thehobsons.co.uk
Thu Oct 29 08:17:03 UTC 2009

shishir saud wrote:

>The case here is I have two variants of modems. One of those modems 
>comes online without any issues but with the other, they dont appear 
>online. What happens is they broadcast a DHCP DISCOVER and the dhcp 
>server offers them with IPs but then I dont see any requests coming 
>from them. If I revert them to my older dhcp that is running version 
>3.0.2 they all work just fine. The configurations aren't different 
>except there are failover configurations done in the test dhcp 

Well try turning off the failover and see if that makes a difference. 
Assuming it doesn't, then leave it off (makes things simpler) and use 
a packer sniffer to capture and decode the packets off the wire - do 
this for the working and non-working versions and see what 
differences there are.

My guess is that the modem is picky about some little detail - could 
be as simple as option order in the packet (shouldn't be, but 
wouldn't be the first broken client).

Simon Hobson

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