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ecstech

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Weird LAN problem causing network drive lost

I run a small LAN Domain with less than 20 PCs. All running Windows XP Pro SP3.
The server running Windows 2003 standard server R2, SP2.

It's been up and running for several years.

Last week a user came across an odd problem. In the morning, he switches on the PC and logs in. During the course of the working day he'd lose the ability to open his network drives. Only logging off and back on seemed to work for him.
It's as if the server thinks he's not logged in any more.

I examined his PC and can find nothing wrong with it and no other users, all on the same domain, were reporting issues.

I did a few tests myself on my own XP Pro sp3 machine and did discover an odd problem.
On normal day-day logon my logon batch script adds various network drives to resources on the Server.

If I run another batch script that simply does:

@ECHO OFF
:loop
net view /domain:ECSTECH
wait 2
goto loop

then I get a listing like this:

System error 51 has occurred.

Windows cannot find the network path. Verify that the network path is correct an
d the destination computer is not busy or turned off. If Windows still cannot fi
nd the network path, contact your network administrator.

System error 51 has occurred.

Windows cannot find the network path. Verify that the network path is correct an
d the destination computer is not busy or turned off. If Windows still cannot fi
nd the network path, contact your network administrator.

System error 51 has occurred.

Windows cannot find the network path. Verify that the network path is correct an
d the destination computer is not busy or turned off. If Windows still cannot fi
nd the network path, contact your network administrator.

System error 51 has occurred.

Windows cannot find the network path. Verify that the network path is correct an
d the destination computer is not busy or turned off. If Windows still cannot fi
nd the network path, contact your network administrator.

Server Name            Remark

-------------------------------------------------------------------------------
\\AUREUS               ECSTECH SERVER
\\ECS3              
\\ECS5              
\\ECS6
\\ECS11              
\\ECS14               Stuarts PC
\\ECS17               SCANNER
\\ECS19              
\\ECS23            
\\ECS24              
\\SERVER               ECSTECH SERVER
The command completed successfully.

System error 51 has occurred.

Windows cannot find the network path. Verify that the network path is correct an
d the destination computer is not busy or turned off. If Windows still cannot fi
nd the network path, contact your network administrator.

System error 71 has occurred.

No more connections can be made to this remote computer at this time because the
re are already as many connections as the computer can accept.


etc...


When I run this net view script and have a network drive open via 'my computer' then the net view command NEVER fails.
But when I close the network drive, within minutes the error 51 returns. If I have a network drive open it never fails.

I've looked in the event logs of the XP client and can't find any errors.

Any clues to what I need to look for?


Internet ProtocolsWindows NetworkingServer Hardware

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Last Comment
ecstech
Avatar of cobra09
cobra09
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When was SP3 updated? Was the issue happening after the SP3 upgrade?

What about the Windows Firewall? Is it in disabled state?

If Yes, does the Firewall give error when trying to start?
Avatar of ecstech
ecstech

ASKER

Thanks for answering Cobra09.

No, SP3 been on all of the machines for at least 6 months.
All PCs get Microsoft Auto-update every day.


I don't think it is a firewall issue. I tried leaving the Server Firewall off and it made no diff.


I did some tests this morning.

Set up two Windows XP Pro SP3 machines I've had on the netowork for ages and logged into both of them using a dummy 'user' domain account and ran two batch files side by side on each PC.

One script does a looped NET VIEW and the other does a looped NET USE

Ran these two on both machines.

On PC-A if I try to open a network drive via my computer, it often fails (I get G:\ is not accessible. Windows cannot find the network path..) , I retry to open and eventually it opens.

When this drive becomes open then NET VIEW works and NET USE shows the drive is connected.
But when I close the network drive, then the NET USE immediately shows it's disconnected!
And as soon as it is disconnected, NET VIEW stops working.

If I do the same on PC-B, then I can open a network drive no bother at all in My Computer, and when I close it, the NET USE shows me that the connection is not dropped. This is correct as the Server is set to keep connection open for 60 mins.

So both PCs are running XP PRO SP3 and are logged into using the same account, so GPOs will be the same between them.

I've also got a portable and at least one other PC behaving like PC-A.


 


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ecstech

ASKER

I've done a few more tests.

I created a new account on the server with the same level of permissions as the previous accounts.

I logged into PC-A and saw the normal logon.bat script running.

I did a looping NET USE, which gave me a list of connected network drives (all ten of them) and they were all connected. They remained connected.
Which is good!

Then I did a manual single NET VIEW and I was amazed to see a System error 51 occurred and in te still looping NET use window I saw all the network drives instantly disconnected and now display Status: Reconnecting.....

On opening the 'My computer' window,this turned into a list of status :OK.... so they all became 'live' again.

On running the looping NET VIEW I see it working 100% and the NET USE drives remain all OK.

This got me wondering. Does XP PRO have a upper limit on the number of network connections and have I exceeded this? I thought it was in the order of 20 or so.

I'm baffled.


Avatar of ecstech
ecstech

ASKER

I wonder if netbios is broken?

I run netbios browsing console on the server and it looks fine.
It idents the master browser.

When I run the Browstat diagnostic program on a failing client PC I get this worrying message when I perform it repeatingly.

(GAIA is the Server) ECSTECH is the domain.

C:\>browstat status


Status for domain ECSTECH on transport \Device\NetBT_Tcpip_{305CE30A-DFEA-492C-AB16-ABFAAB
0531EB}
    Browsing is active on domain.
    Master browser name is: GAIA
        Master browser is running build 3790
    1 backup servers retrieved from master GAIA
        \\GAIA
    Unable to retrieve server list from GAIA: 51

C:\>browstat status


Status for domain ECSTECH on transport \Device\NetBT_Tcpip_{305CE30A-DFEA-492C-AB16-ABFAAB
0531EB}
    Browsing is active on domain.
    Master browser name is: GAIA
Could not connect to registry, error = 53        Unable to determine build of browser mast
er: 53
   Unable to determine server information for browser master: 51
    1 backup servers retrieved from master GAIA
        \\GAIA
    Unable to retrieve server list from GAIA: 51

C:\>

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Windows Networking
Windows Networking

The Windows operating systems have distinct methodologies for designing and implementing networks, and have specific systems to accomplish various networking processes, such as Exchange for email, Sharepoint for shared files and programs, and IIS for delivery of web pages. Microsoft also produces server technologies for networked database use, security and virtualization.

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