timeout on first connection

Hello

I have the problem that on one of my server users get a timeout on the
first connection attempt (somtimes even on the first two).

I was really not able to track down where the problem is (os, web
server or web application)

It is apache Apache/2.2.0 (Linux/SUSE).

Tried also ethereal, there I see that the server sends back a tcp frame
with the reset flag set, and then the connection times out in the users
webbrowser (this is for a ssl connection).

After a successfull connection it is no problem to surf the website,
but after a few hours the same thing starts again.

So I wonder why the server resets the connection on the first attempt?