Default gateway address keeps resetting

Hi Group,

I've come up against this situation once before but used a workaround in
that particular situation, this time I could really do with understanding
why the problem occurs and resolving it once and for all so your input would
be gratefully appreciated. Here goes:

The IP of the default gateway on a clients network had to be changed (it
went from 192.168.10.16 to 192.168.10.20). All client machines use DHCP so
this was updated by modifying the scope and all is well in that respect.
There are 5 servers on the network all with static IP settings and these
have been duly updated too. However, in the case of three of these servers
(two are Win 2003 Enterprise running Terminal Services and the other is a
Win 2003 Standard), whilst they accept the updated settings and use the
gateway fine for a while, they keep reverting back to the old gateway
settings. I can't find anything about this on the knowledge base but given
that I've experienced it with two completely separtate networks now, I
figure that I'm either missing something obvious or there is perhaps a known
bug/resolution that I'm unaware of.

All the best,

Simon

Routers have the ability to modify routes on machines even if a routing
protocol (like RIP) is not being used. But they usually only do it if the
route is wrong.

For instance, if you send traffic to a particular gateway and that
router(gateway) knows that the best route is via some other gateway it will
redirect the traffic. It will also send an ICMP message back to the sender
informing it of the better route. The client will then usually update its
routing table with the info.

Does the old gateway still exist? Does the new default gateway have any
routes pointing to it? Are these problem machines machines multihomed (so
that there is an alternative route to the target)?

Simon Guest wrote:
> Hi Group,
>
> I've come up against this situation once before but used a workaround
> in that particular situation, this time I could really do with
> understanding why the problem occurs and resolving it once and for
> all so your input would be gratefully appreciated. Here goes:
>
> The IP of the default gateway on a clients network had to be changed
> (it went from 192.168.10.16 to 192.168.10.20). All client machines
> use DHCP so this was updated by modifying the scope and all is well
> in that respect. There are 5 servers on the network all with static
> IP settings and these have been duly updated too. However, in the
> case of three of these servers (two are Win 2003 Enterprise running
> Terminal Services and the other is a Win 2003 Standard), whilst they
> accept the updated settings and use the gateway fine for a while,
> they keep reverting back to the old gateway settings. I can't find
> anything about this on the knowledge base but given that I've
> experienced it with two completely separtate networks now, I figure
> that I'm either missing something obvious or there is perhaps a known
> bug/resolution that I'm unaware of.
> All the best,
>
> Simon

Hello Bill,

Thanks for your response.

The old gateway no longer exists on the network - indeed there is no device
at all using this old IP address. The only gateway/route from the network
is the new gateway. All the other servers seem to obey the updated setting
without issue except these three. It really does just seem to be a case of
Windows 'remembering' the old setting and then reverting the gateway
settings back to it, but never straight away. Whilst ever the TCP/IP config
has the new gateway settings in place, it indeed does use the correct
gateway without issue.

Weird but true...

Best Regards,

Simon

"Bill Grant" <not.available@online> wrote in message
news:%23RhZo$(E-Mail Removed)...
> Routers have the ability to modify routes on machines even if a routing
> protocol (like RIP) is not being used. But they usually only do it if the
> route is wrong.
>
> For instance, if you send traffic to a particular gateway and that
> router(gateway) knows that the best route is via some other gateway it
> will redirect the traffic. It will also send an ICMP message back to the
> sender informing it of the better route. The client will then usually
> update its routing table with the info.
>
> Does the old gateway still exist? Does the new default gateway have any
> routes pointing to it? Are these problem machines machines multihomed (so
> that there is an alternative route to the target)?
>
> Simon Guest wrote:
>> Hi Group,
>>
>> I've come up against this situation once before but used a workaround
>> in that particular situation, this time I could really do with
>> understanding why the problem occurs and resolving it once and for
>> all so your input would be gratefully appreciated. Here goes:
>>
>> The IP of the default gateway on a clients network had to be changed
>> (it went from 192.168.10.16 to 192.168.10.20). All client machines
>> use DHCP so this was updated by modifying the scope and all is well
>> in that respect. There are 5 servers on the network all with static
>> IP settings and these have been duly updated too. However, in the
>> case of three of these servers (two are Win 2003 Enterprise running
>> Terminal Services and the other is a Win 2003 Standard), whilst they
>> accept the updated settings and use the gateway fine for a while,
>> they keep reverting back to the old gateway settings. I can't find
>> anything about this on the knowledge base but given that I've
>> experienced it with two completely separtate networks now, I figure
>> that I'm either missing something obvious or there is perhaps a known
>> bug/resolution that I'm unaware of.
>> All the best,
>>
>> Simon
>
>