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Q: Connection issues after applying Server 2003 SP1

after installation of w2k3 sp1 i have serious tcp problems. the problems:
- 3-5% ping loss to *any* non-localhost-ip
- ftp uploads fail if file size is greater than 8kb ("unable to open data connection" / "data connection timeout")
- outlook express fails to send out smtp mails ("unable to connect to server")
- vpn connection breaks up every other minute

the setup:
- this is an out-of-the box configuration. the machine has 2 different interfaces, both having these problems.
- windows firewall is disabled.
- tcp/ip filtering is disabled.
- windows 2000 on same machine works fine!

the workaround:
- packet loss: no clue so far
- sending out mails: when resetting the network interface (i.e.: disabling/enabling the nic), operation works for a few minutes as it should.

it looks like some problems with the tcp-ip stack here. connecting to the target socket works, but resulting in a timeout from time to time before any data is sent.

any pointers how to further test and elaborate the problem is more than welcome! i've spent hours trying and countless reinstals to solve this problem without any luck.

would be sad to switch back to w2k ;-(

- thomas

A: It could be the MTU issue. (Note: check this page for the details


Reply: cheers robert

this fixed my problems partially. indeed the max. MTU size my router(s) can  use is 1372. setting the MTU value for PPP and VPN cured the packetloss.

unfortunately, this didn't cure the ftp / mail / news upload problems:

[23:17:24]     PORT 192,168,2,141,8,171
[23:17:24] 200 Port command successful.
[23:17:24]     Opening data connection IP: PORT: 2219.
[23:17:24]     STOR id.jpg
[23:17:24] 150 Opening data connection for id.jpg.
[23:17:24]     2368 bytes sent successfully. (2.31 KB/s) (00:00:01).
[23:17:54]     No response received from server. Timeout (30s).
[23:17:54]     Connection closed.

while the ftp tool (here: smartftp, but same behaviour in comand line ftp) thinks the 2368 bytes were sent successfully, the target server never got any bits and bytes (id.jpg got size of 0 bytes on server). the 2368bytes
thus are put into the tcpip buffer where it *should* be sent by winsocks. the application itself isn't even notified of any sending errors. only 30s (after timeout waiting for server response) its socket is closed.

the interesting part: once the upload failed, a 2nd upload after the connection timeout is most the time successfull. i got no clue, but i would describe the problem as something like "delayed outbound socket creation"

this behaviour somewhat describe the same problems as discussed here:
unfortunately, KB893066 cannot be uninstalled in a slipstreamed w2k3 sp1... and of course uninstalling an important hotfix is the least you want to do anyway. but still better than not being able to use your windows
installation for your work...

- thomas


Related Topics

Troubleshooting Windows Server 2003 SP1 Issues,
Case Study


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