[ubuntu-uk] DNS settings resetting

Colin Law clanlaw at googlemail.com
Sat Jan 16 08:45:28 GMT 2010

2010/1/15 James Tait <james.tait at wyrddreams.org>:
> Hash: SHA1
> Colin Law wrote:
>>>> I have looked for clues as to why the DNS settings might be
>>>> disappearing but have not found anything logged anywhere, suggestions
>>>> as to where to look for information would be much appreciated.  Or any
>>>> other ideas for that matter.
> DHCP transactions or normally logged by dhclient in /var/log/syslog.
> You should be able to grep for dhclient and see what IP address you've
> been offered and by what server.  Also, NetworkManager logs the DHCP
> information it gets in the same file.

Got that, thanks, I am not sure why I did not see those when I initially looked.

>> I suppose one possibility is that when the PC asks for the lease to be
>> renewed the router is not providing the DNS correctly.  That seems an
>> odd sort of fault however.  It has only recently started happening.
> It sounds a bit like you may be getting a lease from a different server
> on your network.  Has anything recently been added to the network that
> could be acting as a DHCP server?  A new computer, router, access point?

There is just the laptop that is seeing the problem and two other
Ubuntu PCs on fixed ip addresses (plus the router).  I have recently
added one of these PCs so I suppose I may have accidentally enabled a
dhcp server on it, though not sure how.  I will disable dhcp in the
router and see if the laptop finds a server.

Otherwise I will wait till it fails again and see what is in the log.



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