dhcp-users Digest V1 #235

[Anthony Papineau]

> From: Bruce Hudson <Bruce.Hudson at Dal.Ca>
> Subject: Re: strange DHCPDECLINE behaviour on fixed/static address
> Date: Tue, 28 Nov 2006 14:27:42 -0400 (AST)
>
>> What is the client supposed to do if the server deny's the
>> DHCPDECLINE message?
>
>     The server cannot "deny" the DHCPDECLINE message. It is a  
> status back
> from the client telling the server that it did not accept the  
> address. The
> normal reason for this to happen is that the client is seeing that the
> address is already in use on the network.

If that is the case, then what does the 'allow/deny/ignore' decline  
keyword option in dhcp.conf actually do?

>     If you are using fixed addresses, there is no pool to remove  
> the address
> from. The server offers the same address again since you've  
> configured it so
> that is the only offer it can make.
>
>     If you've configured the address into a pool as well as  
> assigning it as a
> fixed address, that is a configuration error you should correct.  
> The server
> does not try to out-think the administators to protect them from  
> them-selves.

The address is/was NOT assigned to a pool as well as fixed. In fact  
there was actually no conflict on the network when this problem  
occurred - the system was having a hardware failure and this appears  
to be a symptom of it.  There were no other systems on the network  
with the same IP assigned.

However since the address is fixed and there was nothing that could  
be done in the dhcp server to resolve the problem I was hoping there  
was a way to tell the DHCP server to ignore that client, or send a  
message to the client to 'go away' for a while.

>     If you want to eliminate the looping requests, determine who  
> else is
> using the address and stop them. If you have given out the address  
> through
> DHCP and have a short enough leave, changing the configuration and  
> waiting
> may be enough. Otherwise you may need to shut down the DHCP server  
> and the
> offending client, edit the lease file to remove the bad lease,  
> restart the
> server, and reboot the client.

The problem was that this happened overnight - since the client made  
multiple re-requests every second, the system log got very huge very  
fast, to the point where it filled up several gigabytes.


<><><><><><><><><><><><><><><>
Anthony R. Papineau
Systems & Network Administrator
Exegenix Canada, Exegenix Research
416-762-2433, 416-762-2453(fax)
http://www.exegenix.com