[En-Nut-Discussion] Webserver Image problem

[Dusan Ferbas]

This can be called also a 'TCP sockets and FIN/RST packets' problem.

I have a tcpsm.c rev 1.6 with rentrasmition timer correction. But even with 
this I encounter lost FIN.

Somebody earlier suggested 120 sec renewal period. I need 5 seconds.

The more packets are used for 1 html the more probable is FIN lost. In this 
case TCP connection end looks like:
Nut < -- > Windows XP Pro
ACK, FIN ->             (Nut initiated socket close)
         <- ACK
         <- ACK, FIN
missing FIN
         <- ACK, FIN     (rexmitted after 2.4 sec)
RST -> (it looks like socket has been closed and port no more exists)

I know that sockets are put to a close wait state to wait for last FIN. 
This is usually called lingering (am I right ?). Then another socket is 
created and closed socket is waiting until linger end. More complex 
situation occures if TCP stream consists from a lot of small portions 
(fprintf() reason - see previous email) and more threads with sockets are 
opened.

Any idea ?



Dusan Ferbas
www.dfsoft.cz