Got me stumped.....

Got several users at the office who are having the same problem. Once a day at the same time each user loses all network connectivity. The laptops are IBM T23's which are docked while in the office. They are running Win 2k SP4 IE6.0 on a Win 2k domain. IP addresses, WINS and DNS server are assigned dynamically. Other apps include Office 2k, Lotus Sametime, Minitab, Project, Visio, and QWS3270 (3270 emulator). The symptoms are page not found errors in IE, Sametime loses connectivity to server, unable to access mapped drives, etc. Network: Cisco 6500 and 7500 routers with Cisco switches running multiple VLAN's on each switch.

So far I have tried reinstalling IE6.0 and SP4. I have also run virus scan (SAV 8 corp. ed.), Spybot and Adaware. No viruses and Spybot only revealed the usual Gator, Comet Cursor, etc.

Any other thoughts/ideas on how I can troubleshoot this problem?

Thanks in advance.

Yes, being laptops the nic will be allowed to power down. Go into device manager and stop 2k powering down the nic when it thinks its idle.

They all lose connectivity at the same time?

I'd look at the network hardware, see what the logs report at that time.

There may be something interfering with the electrical supply reaching the switches, like an AC unit sparking up at that time.

A little more info....

I checked the event logs and the only event showing is 5719 "No Windows NT domain controller is available for domain XXXX. The following error occurred: Not enough storage is available to process this command." I checked and disk usage is 3.5GB/40GB.

(Note: XXXX is our win2k domain, name omitted)

Also, the three laptops are located in different cities. All are getting clean A/C power and battery health is good.

Hi King,

Give this a try... It is a list of things that could cause what you describe.

http://www.eventid.net/display.asp?e...TLOGON&phase=1

Snow

Thats a lot to read Snowman, but great link! I'll bet the answer is in there somewhere.
What is really curious about this one is the way they shut down at the same time. That to me would indicate a problem with the server and not the workstations.
What do you all think?

May i uggest that this is might be a problem with connectivity device (hub, switch)

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Originally Posted by Gabriel

May i uggest that this is might be a problem with connectivity device (hub, switch)

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I'd agree that's possible especially given KINGofBLEH's last bit of info, but without being privy to the 'wiring' its hard to conclude definately, but very possible methinks ..

Snowbound67's link seems to cover every possibility ! but they all seem to come down to some timing/'slight' mis-configuration at the 'server' (so still maybe switch or whatever) end, again without knowing 'more' hard to comment ..

What time of the day are they losing connectivity? is it around noon? Reason I ask is we had a customer with a similar issue. It turned out they had their backups setup for 12pm (noon) instead of 12am. As soon as the backup started, all users would get punted until it was finished.

If its always happening at the same time, check the building for something that happens around the same time. It may not even be part of your network.

This could be a clue,

One of our customers in London has 2 offices in 2 buidings that are network connected by 2 dishes pointing at each other, (don't know what sort of link it is, possibly microwave?). Earlier this year they would lose connection every now and again at exactly the same time of day from one office to the main network in the other building. After a LOT of work they discovered it was the sun shining at a certain angle into one of the dishes that was causing the loss of comms. Obviously on a cloudy day it didn't happen, and when it did happen it could last up to 15 minutes or until a cloud passed by! That's all the details I can offer, but they cured it by making a permanent shadow on the one dish!

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That to me would indicate a problem with the server and not the workstations.

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I'm with you, TripleRLtd.

It has to be something they all have in common. That's a server.

Could be a dish, but not likely that all three in different cities would be pointed the exact same direction with the same weather and end up all 3 loosing connectivity.

@Damned Angel
I'd also wondered the same thing. I've seen settings 12 hours off before.

I also wonder about other scheduled tasks like anitvirus updates, or maybe some other application activity that could overwhelm a connection device.

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Originally Posted by NooNoo

Yes, being laptops the nic will be allowed to power down. Go into device manager and stop 2k powering down the nic when it thinks its idle.

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Good suggestion Noo, I do this on all systems, 2K and XP, not just the laptops. I don't like windows deciding it's a good time to just power down crucial parts of my hardware for me! :flame:

Heh, a local college put a microwave link in, they kept losing connectivity....every time a bird flew through (and fried) in the wave....

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Originally Posted by NooNoo

Heh, a local college put a microwave link in, they kept losing connectivity....every time a bird flew through (and fried) in the wave....

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Did the canteen do cheap "chicken"?