So you have some PCs exhibiting this and others not? And it doesn't appear
to be related to hardware, in that you have both effected and normally
functioning PCs on the same network segments?

I would probably start by swapping the network connection between a normally
functioning and effected PC (right at the PC NIC). That will let you know
if the problem is on the client PC or not - if the problem follows the
effected PC to the non-effected PC's network connection, it's the PC.

If the problem stays with the wire rather than the PC, I'd probably blame
network cabling or hardware before I'd look at the server. My reasoning is
just that it seems like a server problem (or one between the server and the
switch closest to it) would effect more than just some PCs.



Other suggestions: compare the results of an ipconfig /all from a working
and non-working PC to make sure there are no differences in settings other
than the workstation IP. Check/update drivers on the workstation NICs (and
probably the SBS NIC as well). Swap out all the network cables relating to
anything that's not working properly.

Does anything appear to trigger this, or is it just random? Any other
symptoms? Any wireless involved?


"SteveM" wrote in message news:xn0giqe4w5eryk000@newsgroup

>I have a client with a SBS2003 running 15 clients over an Ethernet-only
> LAN, and some users are experiencing network disconnections once or
> twice a day when browsing a common share (mapped to a drive letter) on
> the server, or attempting to open a Word doc from the share, say.
>
> They lose the drive mapping and mobsync pops up a warning that they
> have gone offline. Choosing to resync corrects the issue.
>
> Client event logs don't offer any clues, but the SBS Security log shows
> multiple 538 and 540 events (many per second) for both the computer and
> user affected.
>
> Topology is single-NIC SBS 2003 through a main 10/100 unmanaged switch,
> with some clients on secondary switches connected to the main one -
> there doesn't appear to be a correlation between the issue and whether
> or not the client is on a secondary switch, though. I suspect a (main)
> switch or SBS NIC hardware issue, but any other ideas or
> troubleshooting tips would be welcome. Thanks.

Dave Nickason [SBS MVP] wrote:

> So you have some PCs exhibiting this and others not? And it doesn't
> appear to be related to hardware, in that you have both effected and
> normally functioning PCs on the same network segments?
>
> I would probably start by swapping the network connection between a
> normally functioning and effected PC (right at the PC NIC). That
> will let you know if the problem is on the client PC or not - if the
> problem follows the effected PC to the non-effected PC's network
> connection, it's the PC.
>
> If the problem stays with the wire rather than the PC, I'd probably
> blame network cabling or hardware before I'd look at the server. My
> reasoning is just that it seems like a server problem (or one between
> the server and the switch closest to it) would effect more than just
> some PCs.
>
> Other suggestions: compare the results of an ipconfig /all from a
> working and non-working PC to make sure there are no differences in
> settings other than the workstation IP. Check/update drivers on the
> workstation NICs (and probably the SBS NIC as well). Swap out all
> the network cables relating to anything that's not working properly.
>
> Does anything appear to trigger this, or is it just random? Any
> other symptoms? Any wireless involved?

Thanks for your suggestions, Dave. I was beginning to go down the lines
you suggest when I found out two other pieces of the puzzle: (1) It
*might* be affecting all users. I have now determined that more users
than I first thought are experiencing the problem, and (2) of those
users who have reported the problem, it seems that the issue might be
happening the first time (in a day) they attempt to access a particular
folder on the server. All users access a share on the server via a
mapped drive (connected through a common login script), and the folder
in question is a subfolder of that share. I don't at this time know how
reliable the user reports are of this (I hope to verify details after
the weekend), but for now I have re-created the folder tree in question
and will see what effect this has. I have also found all sorts of
shortcuts in the share that individual users have created to other
folders and documents in the shared folder tree, some of which are
valid and some not. I have deleted these to narrow down possible
causes, and will have to educate them to keep personal shortcuts just
that: personal (and in their own My Docs folders).

Other than that there is no WiFi on their LAN, and I have verified the
ipconfigs of affected workstations: indeed, I have spent considerable
effort of late to harmonise all workstation configurations and
troubleshoot DHCP, DNS, group policies, profiles and folder
redirection, etc. This network was in a complete mess when I inherited
it, having been set up and managed by so-called IT experts who hadn't a
clue what they were doing and no knowledge of SBS at all. Apart from
this knotty issue, everything appears absolutely fine now, though, and
set up the way an SBS network should be.