intermittent network fault on win2k

[Adam Cox]

We have a domain with a win2k pdc server. We have an
intermittent problem where pc's on the network (inc other
2k servers in the domain) cannot access any network
resource on that server and pretty much hang. However,
during this problem the server can ping and be pinged by
other pc's quite happily (outputting ping logs to a text
file) and the server itself doesn't hang - it can still
access network resouces on itself or on other
pc's/servers. This problem usually sorts itself out within
a matter of minutes.

We have xp pro and win98 stations and 3 other win2k
servers - 1 mailserver in the same domain, 1 which is a dc
for a child domain and 1 which is a dc which has an
external trust relationship. All machine are kept up to
date with latest service packs and patches.

Thanks

 

[Guest]

I have the same problem have you been able to find a
solution??

regards

Marcel

 

[Adam Cox]

Im afraid not - this has been going on for some months
now. We have even had someone in who is a bit of a wizard
with networks and he was baffled. In fact it just happened
whilst typing this. Interestingly our mail server was
doing a remote backup of something on our main server
during this but carried on backing up with no problem.

Adam

 

[Lou C.]

This kinda sounds like a DNS issue. You'd be able to ping because the
NIC's don't disconnect, but they (the servers) are hanging because
they can't find what they need to find via DNS. After a minute or
two, they DO find what they need and all is well.
Any event log errors? Are you 100% sure DNS is properly configured?
Can you run DCDIAG (from win2k support tools) and see if you get any
DNS errors?
Lou

 

[Guest]

I have had a similar issue from a (single) W2k client.
The problem clinet does not start working after a few
minutes and it will not work when using the IP address to
take the DNS out of the picture. Ex: using IE to open the
home page of the local HTTP server by IP address will
fail. Reboot the client and it will work for 16 to 24
hours then it fails. The other W2k clients will work for
many days at a time.

Mike

 

[Lou C.]

Mike,
Your issue sounds a bit different from the above issue. In your
scenario, your machine seems to be losing connectivity, which is why
even using IP's is unsuccessful. You might have a physical network
issue. If you run a ping on the machine on question, it will time out
when the machine is "hanging"? This could be a NIC issue or you might
need to reinstall TCP/IP (doubtful, but possible). The fishy part is
that if you reboot, it is OK for awhile. That is weird.
In Adam's scenario, the machine isn't losing ACTUAL connectivity, it
is just unable to communicate with other machines. Or better, other
machines cannot communicate with IT. This is generally indicative of
a local DNS issue. ADAM - Was this machine upgraded from NT 4.0?
You might have an issue with the configuration of local DNS. I have
seen this issue before with a 2K PDC when it was upgraded from NT 4
and DNS was not properly configured from the beginning. For
example(just one of many DNS issues), if your local DNS is a real DNS
namespace (e.g. yahoo.com) machines could look for a server, e.g.
mainserver.yahoo.com...when they query DNS, they get an actual
response of 208.19.3.4 (instead of the local IP for Mainserver,
192.168.x.x). So, they send their request there, and they get no
reply - But they expect one. In the meantime, they are hanging and
waiting. Then, they cache the IP for that server and try and access
it again at a later point, hanging AGAIN. This was one particular
issue I encountered. Did you run DCDIAG? It would essentially let
you know if you DO indeed have a DNS issue. It would help, even if it
doesn't solve the problem. What happens if you nslookup random
records from a client machine or another server? e.g., "nslookup
crazy"...does it ever get a reply? It shouldn't, but if DNS is
misconfigured like the above example, it might get a reply.