Hung NetBIOS connections?

  • Thread starter Thread starter allancady
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A

allancady

I've started seeing intermittent problems with LAN access. I'm
wondering if anyone can help me out with this.

The setup is a set of seven server machines on a LAN inside a firewall.
It's a very static system, so we built it without a domain, no WINS,
just hard-coded machine names. Local networking is all using NetBIOS
over TCP/IP.

The problem I'm seeing now is, sometimes NetBIOS connections seem to
get hung. I don't understand the internal workings of NetBIOS well
enough to understand exactly what this means, but the symptom is, a
scheduled job that temporarily maps a network drive starts failing the
mapping (returns no drive letter). Once it fails, it seems to continue
to fail until I restart the machine.

The only tools I know of to diagnose this are NET USE and nbtstat. NET
USE shows no open connections. nbtstat -s shows the following:

Local Area Connection:
Node IpAddress: [192.168.0.4] Scope Id: []

NetBIOS Connection Table

Local Name State In/Out Remote Host Input Output
------------------------------------------------------------
JIM <00> Connected Out DAVE <20> 1GB 123MB
JIM <00> Connected Out BOB <20> 1GB 132MB
JIM <00> Connected Out GEORGE <20> 340MB 392MB

I'm guessing that it's those open connections that are getting in the
way of the drive mapping. But I don't know any way to flush them other
than rebooting.

Can anyone help me?

Thanks.

-Allan
 
How many computers do you have in the LAN? I am thinking you may setup Domain network, perhaps WINS.

Bob Lin, MS-MVP, MCSE & CNE
Networking, Internet, Routing, VPN Troubleshooting on http://www.ChicagoTech.net
How to Setup Windows, Network, VPN & Remote Access on http://www.HowToNetworking.com
I've started seeing intermittent problems with LAN access. I'm
wondering if anyone can help me out with this.

The setup is a set of seven server machines on a LAN inside a firewall.
It's a very static system, so we built it without a domain, no WINS,
just hard-coded machine names. Local networking is all using NetBIOS
over TCP/IP.

The problem I'm seeing now is, sometimes NetBIOS connections seem to
get hung. I don't understand the internal workings of NetBIOS well
enough to understand exactly what this means, but the symptom is, a
scheduled job that temporarily maps a network drive starts failing the
mapping (returns no drive letter). Once it fails, it seems to continue
to fail until I restart the machine.

The only tools I know of to diagnose this are NET USE and nbtstat. NET
USE shows no open connections. nbtstat -s shows the following:

Local Area Connection:
Node IpAddress: [192.168.0.4] Scope Id: []

NetBIOS Connection Table

Local Name State In/Out Remote Host Input Output
------------------------------------------------------------
JIM <00> Connected Out DAVE <20> 1GB 123MB
JIM <00> Connected Out BOB <20> 1GB 132MB
JIM <00> Connected Out GEORGE <20> 340MB 392MB

I'm guessing that it's those open connections that are getting in the
way of the drive mapping. But I don't know any way to flush them other
than rebooting.

Can anyone help me?

Thanks.

-Allan
 
NetBIOS over TCP/IP without a name server is legacy (even with a name server
is just for backward compatibility). It's always been flakey. But it sounds
llike a general connectivity issue. When the mapping fails, can you resolve
the name? i.e., from the run dialog can you \\computername? How about
\\IP-Address ? Can you ping? With all these server OS's, why not install
WINS? And if they're Windows 2000/2003 it all works SO much better with an
Active Directory and DNS.

....kurt
 
Thanks for replying.
When the mapping fails, can you resolve the name? i.e., from the run dialog can
you \\computername? How about \\IP-Address ? Can you ping?
Click to expand...

Good questions. I went ahead and restarted all the machines last night
(needed to anyway to install latest Windows updates), so at the moment
I can't test it... I'll have to wait until the next time it fails.
With all these server OS's, why not install WINS?
Click to expand...

We actually had WINS set up initially. After a little while, it just
seemed like one more component to maintain that wasn't really
accomplishing much (and a single point of failure), so I turned it off.
In two years, the machine configuration of the system hasn't changed
at all, so just leaving the names static seems like a reasonable way to
go. Most of the time it all works just fine.
And if they're Windows 2000/2003 it all works SO much better with an Active Directory and DNS.
Click to expand...

I believe you there... I do get the impression that the setup we have
is pretty unconventional these days. But when I set it up, I was a
novice sysadmin (it's still not my forte), and I was trying to keep
everything as simple as possible. I had had one prior experience
trying to set up a domain controller that didn't go very well, so I was
trying to avoid that pain.

But the question I would like an answer to at the moment, that I still
don't have is, is there a way to flush those connections without
rebooting?

Thanks,

Allan
 
Well, lucky me, the job failed again last night AFTER I rebooted.
When the mapping fails, can you resolve the name? i.e., from the run dialog can you \\computername?
Yes.

How about \\IP-Address ?
Yes.

Can you ping?
Click to expand...

Yes.
 
(e-mail address removed) wrote in
But the question I would like an answer to at the moment, that I
still don't have is, is there a way to flush those connections
without rebooting?
Click to expand...

Right-click "My Computer"
Select "Manage"
Under "System Tools", open up "Shared Folders", select "Sessions"
Right-click in window, select "Disconnect all sessions".

HTH,
John
 
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