I came to this scenario by chance.

I was having problem with my static IP ADSL internet access.
My upstream (384K) is slow until timeout but downstream(512K) is okay.
upstream -> download office file from remote/home
downstream -> download remote file from local/office

I have two Linux servers (slack9) running apache 1.3.27 and php 4.3.2, mysql 3.2.56. My php program uses the mysql tables and it loads very very slow and sometime will time out.

I port the same program over to my Ms Win 2k server, with mysql and php as well. Amazingly it runs much better than on my Linux.

At first I taught my provider link is having problem because the slow link happens on both my Linux servers. Now that it can run on w2k (even though it's not as fast as it should), I am not sure anymore.

Did anyone encounter this kind of scenario?
Hope some one will be able to explain what might have happened or try your wildest guess.

Not a hardware or software fault...

My telco traced the fault to their own exchange, they changed the port and it works fine now. Upstream and downstream are back to normal operating level.

Phew!!! Well, thank you gor all teh guesses. It's a very good lesson for me. Tried with almost all different hardware and patch with all the recent patches.

In the end... telco problem....