Re: Why is DHCP table empty on Linksys router

From: Al C. (no.spam.acanton_at_adams-blake.no.spam.com)
Date: 08/26/04 

Date: Thu, 26 Aug 2004 10:44:46 -0700

Jeroen Geilman wrote:

> Al C. wrote:
>> Re: Slackware 9.1
>> On my BEFSR41 there is only one machine currently up... mine. When I go to
>> the web-based config screen for 198.162.1.1 and I go to Status tab and
>> Local Area Network and click the DHCP button, there are no machines listed
>> in the table. Obviously the router assigned me an address but it does not
>> show.
>>
>> When wife turns on her laptop and logs in, the table only has one entry:
>> 198.162.1.102. What happend to my machine, which I assume is ...101?
>>
>> Everything seems to work OK, but I would think that my machine would show
>> up on the table as well?
>
> Do you forward any services to your box ?
> Chances are that it won't show as a dynamic address in that case.
>
> ACK - be careful with "obvious" assumptions!
> Do you *know* for a fact that it's using DHCP ?
>
>

This may be the answer. It's from a Usenet posting. I never totally trust
Usenet, but it seems reasonable.

DHCP is really only used when the PCs on your network are turned on and
request an IP address. The DHCP table in the Linksys router (I'm using one
as well) shows the DHCP requests that the router has answered since it was
turned on (or reset). If you reset the router it resets the table, and the
table won't be populated again until a computer is rebooted, or the IP
addresses are released and renewed. This doesn't affect operation, since
the computers on your network already have their IP addresses assigned. You
might run into a problem with IP address conflicts if you have a large
number of computers on your network that are frequently coming on and off,
but DHCP should have a method to resolve this. I'm not familiar enough with
the details of the protocol to know how it handles addressing conflicts.
-----------

The reason that I see the second machine is because it is turned off each
night and rebooted in the AM while my machine is on 24/7 and the DHCP table
"forgets" about it after a lease has expired.... or something like that. I'll
bet that if I reboot my machine it will end up back on the table ... at least
for a while.

Al