tcp/ip ACK timeouts on 2000 server

  • Thread starter Thread starter barb g
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barb g

Win2k SP4 server, XP clients.
The clients complained that "the network is slow". After
spending a lot of time getting to understand what the real
complaint was, we found that one server seems to lag when
processing network requests. We had a networking guy come
out and slap a sniffer on network switch, and he
determined that this particular server was giving "ACK
timeouts", generally greater than 200ms.
But, his job is only to tell us what's wrong. I have to
try now to FIX it!

I've spent some time on the Knowledgebase, but I'm not
finding any solution. Any ideas here?
Thanks,
Barb g.
 
Is the server not acknowledging client requests,?

Are the clients not acknowledging the server's initial SYN request?

Or, do both connections (the 3-way) complete successfully, and subsequent
communications simply start to fail?

In addition, how is overall server performance (i.e., available memory, CPU,
etc.).

It would also help if you could post a trace (perfmon, or better still
windump).
 
Requests are ultimately acknowledged, but take a long long
time. Anytime they try to open files from shared folders
on that server, it takes a very long time for them to
open, for the folders to finally display their contents,
etc. And, it's not just Office files.

What is a "Syn request" and how would I find that out?

The server itself is very robust (1GbRAM, Xeon processor,
huge drives mostly empty and not fragmented); generally
the cpu and RAM are under 30% usage, but when a client
tries to open a file or grab some data from the server,
the CPU then pegs to 100%.

I need some handholding here, since I'm just the fixit
gal, not the install, configure and optimize gal!
Windump? Perfmon is performance monitor, I know. I tried
saving a 2 hour log, but apparently didn't do it right,
because when I went back later, there was no log! I'll
try again.
 
anyone?
I've done what I can to make sure the XP clients are optimized:
I've removed QOS, and all the unnecessary network protocols so they now
only have MS networking client and TCP/IP running. Disabled XP
Authentication stuff. Verified the NIC drivers are the newest. Set
them all to 10MBs/Full Duplex. Hacked out any unnecessary drive
mappings. Looked at that SMB problem article, but we're not seeing any
of those particular errors/error messages, and I've already applied the
other SMB workarounds, though i'm not clear if they should be on the
clients or the server; currently they're both set.

still, throughput sucks, and the server is still the seeming roadblock here.
 
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