Network problem

First off, I dont know a great deal about networks, so bear with me :). Anywho, a day nor two ago a problem started with the network here at my dads office. All the computers (there are 6 in total I think) are networked together (using hubs and whatnot) to the server computer, which connects to the internet with a 128k ISDN line. So with this, all the computers can browse the internet at the same time, and access shared files from each other. Anywho, a few days ago all but one of the computers lost being able to connect to the internet (yet they could acess the shared network files fine). The one computer that still can access the internet cannot access the shared network files. Anyways, origionally I thought it might be a hub problem, but we tried switching the hub port that the computer that could connect to the internet on, but it didnt make a difference (it was still the only one that could connect), so I _think_ that rules out the possibility of a faulty hub. So anyways, my current thought is that since this its through an ISDN line it must be using "Internet Connection Sharing" (I didnt set the network up or anything, so I dont know). If it is, then im guessing that it could be a problem with that, although im not sure. If thats possible would there be a way to check the status of the ICS? If that probably isnt the problem, then does anyone know what could be wrong? Thanks for any help!

Oh yeah, the host computer is a "WinNT Server" if it matters.

First, I'd double check the cable connecting the computer w/internet to the hub. Then you probably want to double check it's netword card to make sure it didn't die. The fact that it can't see shared files and the others can't see the net, makes it sound like a hardware problem between it and the hub (especially since it just randomly stopped working).

Thanks for the reply :). Anyways, I've checked the cables lots of times, they all seem to be in nice and tight. On the computers that cant access the internet, they all happened at different times. One of them happened I think 3 days ago, then mine happened the next afternoon, im not sure when the rest went bad though. But do you think that it could be the network card on the host, I'd think that it would either be an "all-or-nothing" situation if it went out, could be wrong though?

I don't really know much networks either (it was a major victory when I finally got my laptop and desktop connected), but is there something special about the computer that still has internet access? Something that, if it failed, would isolate that computer from the rest of the LAN but not remove its internet access?

Well the guy that uses the computer here at the office was looking for something like that. The only thing that he could find was that his computer didnt have AOL on it and all the others did (that was the old ISP for the office, ugh). So anyways, he said that he got rid of AOL on a different computer, but it still didnt fix anything. That's all that I heard, although I havnt been on the computer that can connect at all.

For what it's worth (and yes, I know it's not much), I'd put my money (and yes, I know it's not much) on the computer that still has internet access.
All of the computers except one have been affected in the same way. So, assuming there's only one fault, you can conclude that those 5 computers are OK (not very likely that the same fault occured on all computers). That leaves the one computer that's 'different.' Can you disconnect that computer from the LAN and see if the other computers behave normally?

Well I can unplug it from the hub, ill try that...(just got back), it didn't seem to do anything different.

Could you provide more detail on the setup?

I'm just taking guesses for now.
Try this first:
Ping each IP address from the host PC and see if that works. That should tell you if it can talk to the other computers. Also try to ping the IP of the host from the other PCs.

Since the LAN still apears to be functional I'd say maybe your cable from the host to the hub is bad (try replacing the cable with another one) or maybe networking on the host PC has been disabled.

Alright, well I just tried some pinging from my machine (which is one of the 5 that cant access the internet), and it can ping the host fine. Then I went over to the host and pinged this machine, which also went through fine.

Heres a bit more info on the network. The 6 or so questions are things that some people on another forum asked:

I'll answer these the best I can, but im not positive on all of them, since I didnt set up the network.

"I know its gonna sounds stupid but it isnt a Firewall thing is it?"
I dont think so, I checked the host, and no firewall is running.

"So have any of the 5 ever worked?"
They were all working fine for about 2 weeks or so, until about 3 days ago one of them died. Then the next day the others did too.


"What network protocols have you got installed?"
Im not sure, how would I find out?

"TCP/IP, are you assigning IP's manually?"
I believe the host automatically assigns IP's

"Have you allowed file & printer sharing?"
Yep

"Can I have a bit more information on the setup please?"
Well im not sure what to give you. The setup is pretty much 5 downstairs computers all connected to a main hub. There is one upstairs computer that is hooked to an upstairs hub which is then hooked up to the main hub. Then the main hub is connected to the host (running "WinNT Server") which goes to the ISDN line i _think_. All the other computers are running Win98, except one which is on XP. The one computer that can access the internet (but not the network) is a Win98 connected directly to the main hub, so its not an upstairs hub/OS problem. Im not sure what else to say, but if you want any more info then just ask (I'll try to find it...).

Also, for anyone wondering why im trying to figure out whats wrong with it, is so we wont have to get ahold of the guy who set the network up, he usually takes a week or two before he can get here :).

this may sound stupid, buit reinstall the whole server! it works with my http server when something goes wrong!

To check the installed network protocols right click on the network neighbourhood and select properties.

Could be your DNS server (converts name -> IP#) has died.

Check that you can ping the network cards, then try with the names. ie "ping server" rather than "ping 192.168.0.1" to test that it can resolve names as well as IP's.

or

Try allocating (to only a pair of test PC's) a static IP address (192.168.0.XXX are LAN only IP's but ping the number first to ensure it is not active before allocating it to a PC).