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

[Simon Kelley]

On 09/10/12 12:22, Lovelady, Dennis E. wrote:
>>> How would I know if a rogue DHCP server has appeared on the net?
>>
>> I don't think it's likely, at the moment. My guess is that the DHCP
>> server is at the same IP address on both the networks, and when the
>> machine came back up, it sent the DHCPINFORM to the DHCP server
>> address, then took the response as confirmation that the lease was
>> still valid. This is a bit of a gray area, but the client isn't
>> strictly allowed to do that: it should send a DHCPREQUEST.
>> (strictly, it should entry INIT-REBOOT state)
>
> You should give yourself more credit, Simon!  :)
>
> Turns out, my ISP had replaced the modem/router while I was away
> (this is in an apartment, and the leasing office let the tech in
> while I was at my real home, and I had complained to the ISP about
> intermittent connection).  Of course, that device had its own DHCP by
> default.  Prompted by your query, I found and resolved the issue
> quickly by disabling that DHCP and using
>
> ifconfig /release; service network restart
>
> (or equivalent) on all devices.
>
> Thanks so much for your guidance; this was one that didn't make any
> sense to me at all, until my eyes were opened again.

Mystery solved. And no need to fix dnsmasq or complain to Microsoft :-)
Glad it's sorted.


Cheers,

Simon.