WIN2k Network Mystery

[scarywoody]

I am on a LAN that has 3 PC's coming off a server computer . 2 out of the 3 PC's cannot access certain web sites (we have a DSL connection). Like buy.com..wwf.com....IE finds the site, but will not load the site. It will sit there then time out. All 3 computers have the same access level. We have tried lowering security levels..installing and uninstalling network cards. Still only one of us can access all sites..while the other 2 of us are limited to certain web sites. Any input would be greatly appreciated..thanks

 

[Guest]

I've heard of this problem, it was actually affecting the entire of BP (Beyond Petrolieum, formerly BP Amoco.) What's happening is actually quite simple, unfortunately I never had to apply this knowledge, so i'm a little sketchy. Hopefully I can help you with it. Basically one of the Win2k computers is running a service that causes it to be an internet gateway for the others. Now when this computer does it, it seems to only snag routes for certain sites, or during periods of active operation. <IE why only certain sites disappear> the end result is that you seem to just find half the internet dead when this computer's not available. The part i'm most sketchy about is this. I think the Win2k machines are polling each other trying to find a proxy. (This is a setting I'm aware of in IE for example, options > internet tools > connection > automatically detect proxy settings)but i'm not sure if the service has to be turned of for polling, or just for accepting the poll and acting as a proxy. <or the name of the process for that matter.> Again, I realize i haven't been super helpful, but i hope this points you in the right direction.
Laterz
-Tracy

<Jedi, Dorsai, Warder, we are those who fill the breech. My lady Nicole holds my heart.>

 

[scarywoody]

Hmmm...does anybody have any suggestions to fix this problem...thanks

 

[scarywoody]

The actual problem that we have is not a "server" side problem. What we have is 4 machines running Win2K. We have one DSL line which goes into one of the machines which has two network cards. That machine simply has Internet Connection Sharing enabled. So basically it is just acting as a gateway. It assigns us automatic IP addresses and we all have automatic detection of proxy settings. All of our computers are configured exactly same, but for some reason unbeknowest to me only one of us can get to certain web sites (ie buy.com, wwf.com). Any help would be greatly appreciated.

 

[Guest]

You are having a Routing Table problem. The machine that is the Gateway should be creating a Routing Table internally that includes all your machines' IP/MAC addresses IF it is the local DNS server. If you have your Gateway system set to Client DNS (getting DNS information from your local ISP) but not running Server DNS for your internal network, then only machines that have valid IP's AND valid DNS settings will be able to get out to the Internet (but not necessarily back). Otherwise there is no Routing Table to direct the other workstations' packets correctly. Say one of your workstations shows a valid internal IP address, and the DNS is set to the ISP Broadcast settings. Any time that workstation sends a packet, it will have the local IP address attached. When this request hits the local Gateway machine depending on how it is configured you could get several reactions. You could see nothing return if the packet addressing stops it at the local Gateway machine, you could see nothing if the local Gateway machine knows to forward it out to the Internet with a valid classfull IP address but there is no Routing Table to return the response back to the local machine, etc...
There are lots of ways to configure your network incorrectly, and only a few working models. I normally use a standalone Router with built in DHCP client/server services as well as RIP2 for Network routing, but you could configure your host Gateway machine to do the same thing.
I might suggest getting a copy of a Network + book, as it will explain all this much better than me, and most likely help you resolve your problem.

Dave
HelpDeskAnalyst

 

[Guest]

I don't believe it has anything to do with routing tables.
The internet connection sharing feature uses Network Address Translation(NAT) which basically replaces the senders ip address with it's own before sending data out onto the net. When the data comes back it recieves it, and then forwards it to the real sender. This generally works, so I don't think it's your problem.

Your problem is most likely related to DNS lookup(although there's plenty of other possible causes)

To test this open a command prompt on one of the comps that doesn't work and type:
nslookup buy.com

If you get a host not found then this is your problem.

if you type:
ipconfig /all

you can check which machine your comp is using for DNS. This should be the server computer. If it's not, open your LAN settings and manually enter this.

anyway, let us know the results of the above and I'll try to get back to you quickly.

 

[scarywoody]

Nope that didn't seem to help...thanks for the suggestion.

 

[Guest]

would you please describe your network topology in detail. Which comp. is able to get complete access to i-net, what happends when the others access I-net? Can you play Network games?What is the Default Gateway IP of the comp. with the two net cards(specifically, the net-card connected to your intranet.)...Try this go to dos prompt of both comps that can and cant access I-net, type: 'ipconfig /all'...compare.
One other thing, how are you accessing the I-net on the comps with limited access? are you sharing IE off of the comp that has access? Or is each comp wired(configed) for its own I-net session.

<P ID="edit"><FONT SIZE=-1><EM>Edited by ashman99 on 12/01/00 09:33 AM.</EM></FONT></P>

 

[James35]

Try this.

Under I.E goto tools,
then internet options,
then to connections,
then to Lan settings,
click off the auto detect settings.
and check
Use a proxy server and then check bypass proxy server
click ok.
click ok.
and try those sites again.

 

[Guest]

I second the vote for correct NAT configuration. If the gateway isnt using NAT, chances are most likely this topo wont work....

 

[scarywoody]

Well we just reformatted the gateway computer, and reset all the network connections and everything is working fine..thanks for the help.