DNS IP Changes

6 Oct 2006 2:01 AM

Larry B.

I have a network that has a small business server 2003, 2 XP Pro, 1 Win2K,
and a PC running vista. This has been in place for about a year and everyhing
has been running just fine until about a week ago.

Here is whats happening:
The server has its IP addresses hard coded, Its also the DHCP server. The
internal IP Addresses are 192.168.17.x. The server is .2 and is setup as the
DNS, WINS, & DHCP for the other PC's.

On the clients they get their IP address from the server and 5 to 10 min
later the DNS server changes to 192.168.1.1. I can do a IPCONFIG /RENEW and
reset the DNS to 192.168.17.2. Then sometime later the DNS changes back to
192.168.1.1. I don't notice this till I try to access the internet and
everything slows down.

I have run Symantec AV, Microsoft Safety.Live.Com, and Trendmicro. none have
found anything. No Virus, no spyware, nada.

I've tried to search the net for leads.

Please help.

6 Oct 2006 11:24 AM

Malke

Larry B. wrote:

Show quoteHide quote

> I have a network that has a small business server 2003, 2 XP Pro, 1
> Win2K, and a PC running vista. This has been in place for about a year
> and everyhing has been running just fine until about a week ago.
>
> Here is whats happening:
> The server has its IP addresses hard coded, Its also the DHCP server.
> The internal IP Addresses are 192.168.17.x. The server is .2 and is
> setup as the DNS, WINS, & DHCP for the other PC's.
>
> On the clients they get their IP address from the server and 5 to 10
> min later the DNS server changes to 192.168.1.1. I can do a IPCONFIG
> /RENEW and reset the DNS to 192.168.17.2. Then sometime later the DNS
> changes back to 192.168.1.1. I don't notice this till I try to access
> the internet and everything slows down.
>
> I have run Symantec AV, Microsoft Safety.Live.Com, and Trendmicro.
> none have found anything. No Virus, no spyware, nada.
>

It sounds like you've possibly got a rogue router on your network.
Perhaps someone brought in a wireless one from home?

Malke

--
Elephant Boy Computers
www.elephantboycomputers.com
"Don't Panic!"
MS-MVP Windows - Shell/User

6 Oct 2006 2:06 PM

Larry B.

Show quote Hide quote

"Malke" wrote:

> Larry B. wrote:
>
> > I have a network that has a small business server 2003, 2 XP Pro, 1
> > Win2K, and a PC running vista. This has been in place for about a year
> > and everyhing has been running just fine until about a week ago.
> >
> > Here is whats happening:
> > The server has its IP addresses hard coded, Its also the DHCP server.
> > The internal IP Addresses are 192.168.17.x. The server is .2 and is
> > setup as the DNS, WINS, & DHCP for the other PC's.
> >
> > On the clients they get their IP address from the server and 5 to 10
> > min later the DNS server changes to 192.168.1.1. I can do a IPCONFIG
> > /RENEW and reset the DNS to 192.168.17.2. Then sometime later the DNS
> > changes back to 192.168.1.1. I don't notice this till I try to access
> > the internet and everything slows down.
> >
> > I have run Symantec AV, Microsoft Safety.Live.Com, and Trendmicro.
> > none have found anything. No Virus, no spyware, nada.
> >
>
> It sounds like you've possibly got a rogue router on your network.
> Perhaps someone brought in a wireless one from home?
>
> Malke
> --
> Elephant Boy Computers
> www.elephantboycomputers.com
> "Don't Panic!"
> MS-MVP Windows - Shell/User
>

Thanks for the idea. I did have another router on the system for the
wireless. I have disconnected it to see if the problem goes away.

6 Oct 2006 2:45 PM

Malke

Larry B. wrote:

> Thanks for the idea. I did have another router on the system for the
> wireless. I have disconnected it to see if the problem goes away.

If you want to have wireless, then set up the wireless router as an
access point without DHCP. Be very very careful about wireless security
at a business. Depending on your business and how you've set up your
network, it could cause a real security problem.

Malke

--
Elephant Boy Computers
www.elephantboycomputers.com
"Don't Panic!"
MS-MVP Windows - Shell/User