XP Pro, Workgroup, shared folders - some PCs can't see main PC just after reboot

[Warrick Wilson]

We have a test network with machines running Windows XP Pro with SP1. The
machines run a set of programs developed in-house. These programs have
worked well on Windows NT 4.0 and Windows 2000 Pro. We're now trying to
upgrade to run on Windows XP Pro.

There is one main PC, with 8 "work" PCs. Each has a shared folder that is
supposed to be fully accessible to the others. The way our software works is
this:

- the main PC copies a file to the shared folder on a work PC
- a program on the work PC recognizes that a file has been dropped, opens
it, does what it was told, and prepares a new file
- the new file is then copied to the shared folder on the main PC
- the main PC recognizes that there's a new file in its shared folder and
processes it
- basically, the main PC drops files on each of the work PCs quickly

If we do this for 5 work PCs, things work OK. Once we go above 5, weird
things start to happen. The result is that the last 3 work PCs given files
can't put their return file into the main PC's shared folder.

BUT ... This only happens on the first go-round once the work PCs are
booted, OR if we wait for 30-60 minutes between running the routine.

HOWEVER ... Once the failures occur, if we run the routine again, ALL 8 work
PCs can reach the shared folder on the main PC and everything works. This
can be in as little as 30 seconds later. Only the FIRST attempt fails. It
doesn't matter what order we visit the work PCs in, either. We've tried
adjusting the order and the last 3 still have problems.

This is different behavior than what we saw running Windows 2000 Pro, and
it's very puzzling.

We've run some audits, etc., and can see that the Guest account is being
used for the access to the shared folder. That's fine - but what can cause
the failure on the first run after booting all the work PCs, but not a run
30 seconds later?

Any suggestions greatly appreciated!

Thanks.

 

[Warrick Wilson]

We have a test network with machines running Windows XP Pro with SP1. The
machines run a set of programs developed in-house. These programs have
worked well on Windows NT 4.0 and Windows 2000 Pro. We're now trying to
upgrade to run on Windows XP Pro.

An update: The Windows 2000 Pro installation got retested on our current
network machines. Same error! This is with the old code that we KNOW we've
done more than 5 machines on. However, that was "back in the day" when we
had PIII 600 MHz machines and 10 Mbps network hubs.

We're now using 2.0+ GHz machines on 100 Mbps switches ... Speed kills, it
seems...

 

[Hans-Georg Michna]

If we do this for 5 work PCs, things work OK. Once we go above 5, weird
things start to happen. The result is that the last 3 work PCs given files
can't put their return file into the main PC's shared folder.

BUT ... This only happens on the first go-round once the work PCs are
booted, OR if we wait for 30-60 minutes between running the routine.

HOWEVER ... Once the failures occur, if we run the routine again, ALL 8 work
PCs can reach the shared folder on the main PC and everything works. This
can be in as little as 30 seconds later. Only the FIRST attempt fails. It
doesn't matter what order we visit the work PCs in, either. We've tried
adjusting the order and the last 3 still have problems.

Warrick,

one possible explanation is that you run into the 10 connection
limit of Windows XP Professional. I suspect that, for some
indiscernible reason, the first connections linger for too long,
so you're temporarily having 2 connections per client, limiting
your number of clients to 5.

For some equally indiscernable reason this seems to happen only
the first time.

I see two ways out.

1. Try to either forcibly close those unwanted connections or
maybe establish some extra connections and close them again or
try to have the drive mapped permanently.

2. Get a Windows server which doesn't have the 10 connection
limit. You may need client licenses.

Hans-Georg

 

[Warrick Wilson]

Warrick,

one possible explanation is that you run into the 10 connection
limit of Windows XP Professional. I suspect that, for some
indiscernible reason, the first connections linger for too long,
so you're temporarily having 2 connections per client, limiting
your number of clients to 5.

For some equally indiscernable reason this seems to happen only
the first time.

I see two ways out.

1. Try to either forcibly close those unwanted connections or
maybe establish some extra connections and close them again or
try to have the drive mapped permanently.

2. Get a Windows server which doesn't have the 10 connection
limit. You may need client licenses.

Thanks for the comments. You are suggesting what we are worrying about - the
10 connection limit. If it happened ALL the time, that would really seem to
be a culprit. But when it "gets better" after the first try, that's what's
really weird.

I think that we're going to attack this two ways -- make our routine retry
the test for availability of the target shared folder, plus look at using
our FTP solution as the LAN-based tranmission method of choice. I'm guessing
that an FTP server would handle more simultaneous connections by default,
even running on XP Pro rather than an actual server OS.

As an aside, is there any way to monitor the shares to determine whether
there's an excess being tried? Our network admin tried using the security
audits, but we never did catch more than 5 at a time.

 

[Hans-Georg Michna]

As an aside, is there any way to monitor the shares to determine whether
there's an excess being tried? Our network admin tried using the security
audits, but we never did catch more than 5 at a time.

Warrick,

there sure is, but I'm not conversant with these things. Perhaps
somebody else can chime in with some good hints.

I guess anyway that you're stumbling over a defect. I guess that
some connections linger after they should have been
disconnected.

Hans-Georg