Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!ucsd!ucbvax!ROBOTICS.JPL.NASA.GOV!litwin
From: litwin@ROBOTICS.JPL.NASA.GOV (Todd Litwin)
Newsgroups: comp.protocols.tcp-ip
Subject: Monitoring TCP/IP sockets
Message-ID: <9101291553.AA06606@litwin.jpl.nasa.gov.>
Date: 29 Jan 91 15:53:17 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 15

I have a program that uses TCP/IP sockets and needs to know quickly, within a
second or so, if the physical connection between the two systems is broken. It
appears that the operating system is very tolerant of physical disruptions, and
won't timeout the connection and formally break it even if the problem lasts
several minutes. I'm using setsockopt() to turn on SO_KEEPALIVE, but this
doesn't help, either. Is there any way that I can force a socket to disconnect
after a second or so of failure to communicate (short of sending my own
heartbeats)? I am running under Sun OS 4.0.2, but also will need to move a
version of this software to the Silicon Graphics world, and to the VxWorks
real-time operating system. Any suggestions would be greatly appreciated.

 		Todd Litwin
 		Jet Propulsion Laboratory
 		(818) 354-5028
 		litwin@robotics.jpl.nasa.gov