Internet connection slows lan

[iroller]

Hello
I wonder would anyone have a solution to my problem. I have a LAN with 1 Windows 2000 server and 45 clients running mostly Windows 98, some ME and some XP home and professional. I have a router that is switched on manually to connect a classroom to the internet but is usually switched off. DHCP is set to steer the clients to the router as a gateway and I’ve also set DNS addresses to link to our ISP. The server is set to dial out every hour to send and receive mail. Both the router and the server use the same connection and both are never on at the same time. (Manual switch) When the server connects the whole network slows down. Clients can’t find the domain server to log in and our LAN based web mail server goes at a crawl. Things improve after the connection stops, but it can take a while to get up to speed. LAN is not as fast as it should be anyway but this is the only time I get an obvious drop in speed.
Any ideas would be welcome.
Sorry if all the technical terms are not correct.

 

[ChicagoTechNet]

sounds like DNS issue. do you have an internal DNS. make sure you have correct DNS settings or use nslookup check it.

For more tips or information, go to

http://www.ChicagoTech.net

Robert Lin, MS-MVP, MCSE & CNE
Windows, Network and How to at

http://www.ChicagoTech.net

 

[iroller]

Thank you. It looks like a very useful site. I am not an expert and I find some concepts hard to grasp.

 

[ChicagoTechNet]

do the easy thing. post the result of nslookup command here.

Robert Lin, MS-MVP, MCSE & CNE
Windows, Network and How to at

http://www.ChicagoTech.net

 

[iroller]

OK
When I use nslookup on the server the following appears:

Server:localhost
Address:127.0.0.1

This was all the first time but when I ran it the second time an extra line appeared:

localhost can't find nslookup: Non-existant domain