[Dnsmasq-discuss] Repeated assignment, ignored dhcp-host, and failed DNS lookup

[Lovelady, Dennis E.]

Hi, Simon:

I have all the logs going back to June, 2011.  (That represents about 70,000 lines of dnsmasq-related messages.)  What would you like to see from those?

The m1330c/w system was on a different network yesterday morning, and moved back to this network in the evening.  Absolutely possible that it is hanging on to its prior lease, though I didn't think those survived a boot after a network switch.  You would absolutely know, though, and I take it from your response that that's probably what happened.  I'll refresh the lease this PM if not back to "normal" by then.

How would I know if a rogue DHCP server has appeared on the net?  I'm assuming you're on the right track since the answer to the remaining question is:

/var/lib/misc/dnsmasq.leases is empty!!!!

Dennis


-----Original Message-----
From: dnsmasq-discuss-bounces at lists.thekelleys.org.uk [mailto:dnsmasq-discuss-bounces at lists.thekelleys.org.uk] On Behalf Of Simon Kelley
Sent: Monday, October 08, 2012 12:04 PM
To: dnsmasq-discuss at lists.thekelleys.org.uk
Subject: Re: [Dnsmasq-discuss] Repeated assignment, ignored dhcp-host, and failed DNS lookup

On 08/10/12 16:43, Lovelady, Dennis E. wrote:

> To summarize:
> 
> nslookup does not return IP address of DHCP-based servers
> 
> "dhcp-host" entries in /etc/dnsmasq.conf are ignored, or at least are 
> not as expected
> 
> Repeated assignment of IP address to two interfaces
> 
>  
> 
> Following are the messages from dnsmasq since time of boot.  What 
> might I be missing?
> 

The log is expected, and not necessarily a problem. The DHCPINFORM transaction is the host asking for configuration information, which dnsmasq supplies in the DHCPACK. It's possible for dnsmasq to reply to DHCPINFORM messages even if a host doesn't actually have a DHCP lease with it.


Questions:

Are there leases for .0.14 and .0.15 in the dnsmasq leases file?

Is there any way to get logs going further back?

Is there any chance that a rogue DHCP server has turned up on your network?

Has the host in question been attached to another network where it could have picked up a different DHCP lease?

My guess is that the .14 and .15 leases don't exist in dnsmasq and the host has picked them up elsewhere.

by now, the DHCP leases on .0.14 and .0.15 may have expired, and the host will fail to renew them and cycle through the DHCP process, getting the correct addresses. If not then taking the interfaces down and then back up, or rebooting the host, should do that.


Cheers,

Simon.




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