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A bizarre networking issue

By michaeld ·
I manage a group of about 35 PC's in a NT Server/Win 98 workstation Fast Ethernet LAN. I use TCP/IP protocol because Internet access is necessary.

I recently updated the 3Com 3C509B NIC's in 15 of these machines with the new Version 6.1 driver in an attempt to resolve an intermittent network communication issue. It didn't help the original issue and added a really strange new one.

I now cannot connect to these machines from "outside", that is, from any machine not having one of these NIC's. I can PING them, and they will pass the 3Com network diagnostics, but will not accept a connection of any kind except from another of this group of 15 PC's. I have full network communication from these machines to any other on the network.

Worse yet, I tried replacing a 3Com NIC with a new Kingston KNE110TX 10/100, and it behaves exactly the same even though 3 other Kingston cards elsewhere in the network behave completely normally. I have done every possible troubleshooting process Ican think of even to the extreme of a 98 SE update, and completely repartitioning, reformatting, and reinstalling of Windows and the new Kingston card (to keep the 3Com driver out of the picture). No luck.

Anybody got any ideas on how to cure this issue?

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A bizarre networking issue

by McKayTech In reply to A bizarre networking issu ...

Wow! that's really weird. It sounds like installation of the 3Com v6.1 driver has implemented encryption on your network. My only suggestion would be a packet trace to see what is actually traveling across the wire. A cure might be something like un-installing the v6.1 driver wherever you find it but I think 3Com needs to get involved in this.

paul

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A bizarre networking issue

by michaeld In reply to A bizarre networking issu ...

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A bizarre networking issue

by mstrong In reply to A bizarre networking issu ...

sounds like the 3com driver has changed the mac address- the install of the kingston would seem to confirm this suspicion/if you have documentation on those numbers before the driver update you can easily confirm this. If no documentation on the origonal numbers, then you'll want to begin the wade through 3coms support page.

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A bizarre networking issue

by michaeld In reply to A bizarre networking issu ...

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A bizarre networking issue

by -Q-240248 In reply to A bizarre networking issu ...

Problems with Fast Ethernet: 10/100 autosensing sometimes doesn't work right. Set your card statically to 100Mbs. Also the 10/100 switch/hub may need to set each port manually as well.

If you can ping, then there is probably not a routing problem, if you even use a router. Since you say you can't 'see' I presume you mean can't attach to a share. Check your workgroup names: They should all be the same.

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A bizarre networking issue

by michaeld In reply to A bizarre networking issu ...

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A bizarre networking issue

by michaeld In reply to A bizarre networking issu ...

First off, my thanks to the three folks who answered so far. In response to their replies (in no particular order):

Already been to 3Com - no help.

The Kingston card was brand new out of the box and so still has its original MAC address. It still exhibits the problem even with the brain-wiped PC that got the clean reinstall of Windows.

I don't use a router internally, and have already tried manual data rate settings where applicable - some of cards, the 3Com ones in particular, are only 10 Mbps anyway.

I got to thinking last night after posting my original question that this has to have something to do with name resolution since the IP address PING is successful. Subsequent trial today seems to bear this out - if I try a Find or a drive mapping using the computer name it fails, but if I use the IP address (I use static IP's), it works. Also did a little digging in Microsoft's Knowledge Base this morning which *seems* to support this theory.

Anybody got any pointers on how to fix broken name resolution?

Thanks again,
Mike

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A bizarre networking issue

by rogerndgreen In reply to A bizarre networking issu ...

Do you have a DNS or WINS server on your LAN?
If you have, are the IP addresses correctly set in the protocols section of network properties? even if they look correct, re-enter them, because sometimes these can get corrupted for no apparent reason.
If you don't have a name server, and you know that you are going to maintain static IP addresses and you ain't gonna change the network much) try creating a HOSTS file & a LMHOSTS (no extensions) into the windows directory which consists of the IP address and machine name, separated by a space, one entry per line.
HTH
Roger

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A bizarre networking issue

by michaeld In reply to A bizarre networking issu ...

That was it - I had been relying only on Browser Service, and for some reason the new 3Com drivers shot that down in flames. Don't know why, but obviously it disrupted the resolution between NetBIOS name and IP address so thoroughly that even putting in the Kingston card didn't allow it to recover.

I went for installing WINS - its marginally easier that messing with copying LMHOSTS all over, and is the preferred method of the two anyway. I'd pretty much come to this conclusion myself this weekend, but your answer convinced me it must be the right approach.

Thanks for your input.

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A bizarre networking issue

by mzy In reply to A bizarre networking issu ...

Just wondered, is it really so bizarre? So difficult to solve? Or maybe if the computers are win98 SE, try using winipcfg (type winipcfg in start menu|run). Select the network you are using, then click renew. Then log on again, I think you should beable to solve the problem. Sounds easy, but I don't know if it will work...it's just a way to try out. Hope this will work for you.

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