Wrong Ip address to the client

Simon Hobson dhcp1 at thehobsons.co.uk
Sun Mar 25 09:20:09 UTC 2012

Ruzsinszky Attila wrote:

>  > Could you send the result of a grep on dhcpd.leases?
>It is a HP Laserjet printer.

He didn't ask for anything from the client, he asked for a grep of 
that IP address from your leases file on the server.

Ruzsinszky Attila wrote:
>  > Will need to know more details :
>>  What is IP address of server - is it ?
> is the Ip of the AP.

Then problem found, see bwlow.

>  > What is in dhcpd.conf ?
>It is a long .conf.
>Which part do you need?

As it happens now, none of it. But normally the answer is all of it - 
though you can cut other subnets or lots of unrelated host statements 
etc. The issue is that if you don't know what the problem is, then 
you don't know what's important - so people have a tendency to cut 
out bits that they think are unimportant but which in fact give vital 

>  > Is there anything else in the logs for ?
>No. Nothing special.

I didn't ask if there was anything you thought special, I asked if 
there was anything.

As it happens, the problem is fairly easy to see now, but in the past 
we've been groping around for ages before some vital bit of omitted 
information comes to light. It may seem picky, but getting everything 
up front is usually better than asking for bits piecemeal.

Anyway, the answer is above.
> is the Ip of the AP

And from earlier :
>DHCPREQUEST for ( from 
>60:d8:19:4d:3d:5e via eth0: lease unavailable

This line says that the lease was offered by (hence 
why I asked what IP address your server has). Your AP is running a 
rogue DHCP server (very easy mistake to make) - turn it off and 
things will sort themselves out.

Probably what's happening is that the AP is getting it's responses in 
first. So after a DHCP-Discover, the AP's offer arrives first. The 
client then requests this, but the AP's DHCP-Ack arrives before your 
server's DHCP-NAck and so the client configures itself with the 
"wrong" address.

Simon Hobson

Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed
author Gladys Hobson. Novels - poetry - short stories - ideal as
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