SP4 install, now no network connections

[juls]

I have a problem with SP4 and ISA server and my Win 2000
file server. No clients can get to the network. My ISA
server cannot see (ping) my file server and visa versa. My
network cards don't seem to be working, but I can get out
on my ISA box using my external card. I uninstalled the
service pack, but it did not fix my problem.
When I look at the status of my network cards they show
very few packets being sent and recieved, it should be in
the 10's of thousands but is only in the thousands. Any
suggestions would be appreciated as my clients cannot
access my servers for files, e-mails, or Internet.
Thanks

 

[joel]

Try this simple registry edit. Worked for me, restored my
internet speed from a crawl/nothing back to blazing. I've
heard it works with other networking issues as well.
THANK YOU STEVE!! He says:

--""I applied SP4 to a workstation running Win2000 Pro and
network performance just dropped through the floor - took
minutes to do even the simplest thing.

I've tracked it down to the registry key

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\
Parameters\Tcp1323Opts

I had to set this to 3 on this machine (to enable scaling
and timestamps) to solve an earlier problem but this
setting with SP4 just seems to grind things to a halt.

If I change it back to 0 (or remove it) then performance
is normal again (except my original problem - why I needed
timestamps in the first place - is back!).

Has anyone else seen problems with this registry key and
SP4?
Cheers,
Steve"

someone else said:

"Seems to be scaling that causes the problem, setting the
value to 0 or 2 is ok - 1 or 3 causes the problem... 0
(disable RFC 1323 options) 1 (window scale enabled only) 2
(timestamps enabled only) 3 (both options enabled)"

I changed the setting to zero (as opposed to removing it),
restarted, and voila!
Wow. I can't believe this worked. I wish I understood
it. Good Luck! And THANKS STEVE!

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 

[Mr. Chuck]

I also had to change:

"HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Enabl
ePMTUDiscovery" = 0

Then all is well again.

HTH

T.