HTTP Server does not finish response
 Technote (FAQ)
 
Problem
The connection between the HTTP proxy and PC client remains in Establish state and will not close. After a timeout occurs, the state changes to FinWait2. FINWT2 state (FINWAIT2) means we have sent a FIN and it has been acknowledged. We have not received a FIN packet from the remote end.

FINWAIT2 state lasts for about 12 minutes, then the connection is cleaned up; however, you cannot get in FINWAIT2 state until the local application closes the connection, demonstrating that the proxy socket has timed out. If the application does not issue a close,
the connection is stuck in ESTABLISHED state.

The sniffer trace shows why the timeout occurred.

The key is the sequence numbers and acknowledgement numbers that are exchanged back and forth. This means there is a byte of unacknowledged data on the connection,
and the TCP protocol requires this data to be retransmitted. Since the packet with the FIN flag has not been retransmitted, the connection is stuck in established state, and you never get a recv of 0.

The only way a sender knows a packet is received at the destination is when the destination acknowledges receipt of that packet.
 
Cause
Windows NT® 4.0 has a known problem of not retransmitting the FIN packet.
 
Solution
Apply Microsoft™ patch q254930 to your Windows NT 4.0 system to solve this problem.
 
 


Document Information


Product categories: Software > Application Servers > Distributed Application & Web Servers > WebSphere Application Server for z/OS > IBM HTTP Server
Operating system(s): z/OS
Software version: 4.0.1
Software edition:
Reference #: 1162579
IBM Group: Software Group
Modified date: Apr 22, 2004