Network freezes up

Tech-Archive recommends: Repair Windows Errors & Optimize Windows Performance

From: SockMeister (SockMeister_at_discussions.microsoft.com)
Date: 02/14/05 

Date: Mon, 14 Feb 2005 08:17:04 -0800

Hello Everyone,

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PROBLEM: Network freezes up.

Over varying amounts of time (2 days up to 3 weeks)
the network on the server side freezes up. All network communication
is lost - can't even ping the box anymore. The app is still runing ok
except for the socket links. Client side machine ok.
Reboot the server machine cures the problem for a while.

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SYSTEM INFO:

NT 4.0 SP6 machines
PIII 850 MHz 256 MB RAM

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APP INFO:

Winsock 2 Client/Server model using TCP/IP.
We control both ends of the connection with both
server and client written in C++. We use our own
socket classes, not based on MFC.

Compiler: Microsoft Visual C++ 6.0 SP5.

Use nonblocking sockets and WSAEventSelect() for
asynchronous notification of network events.

Max of 6 simultaneous sockets connections active at one time.

Server side creates one listen socket which exists for
the life of the app.

Client side connects and disconnects many times for data
transfers. Socket session durations vary and range from
30 seconds to 60 minutes with the average duration at
about 3 minutes.

Client and server machines are connected by a local network
inside the building, no outside internet connection.

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ANALYSIS SO FAR:

- Code reviews to verify that sockets are properly opened and closed, etc.
All appears ok here.

- Review the Windows Sockets 2 API Specification, Revision 2.2.2,
August 7, 1997 Appendix C, "The Lame List". No problems here.

- Runtime resource leak checks using BoundsChecker (through Visual Studio).
No resource leaks are reported in the socket area although there are
some other leaks due to our own leagacy code as well as a residue of
NT leaks.

/////////////////////////////////////////////////////////////////////
WINSOCK FORUMS VISITED:

- http://www.codeguru.com/forum

- http://www.vbip.com/forum

- http://www.msdn.microsoft.com/newsgroups

Has anyone encountered this, or a similar problem?

Any ideas or insight would be greatly appreciated.

Regards, 

-- 
SockMeister

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