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From: louie@SAYSHELL.UMD.EDU (Louis A. Mamakos)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Warning: Keep-Alive considered harmful
Message-ID: <9011191440.AA08953@sayshell.umd.edu>
Date: 19 Nov 90 14:40:15 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The University of Maryland, College Park
Lines: 13

In article <1990Nov19.063111.21768@Think.COM> you write:
>Unfortunately, keep-alives are sometimes needed to work around deficiencies
>in application protocols.  For instance, there's no way for a server telnet
>to detect when the client host has crashed (it could send an IAC
>Are-You-There, but there's no standard for the response, so it would
>confuse the process receiving the input).

The server telnet could periodically send TELNET NOP commands (IAC NOP) to 
the client.  This should not cause any response to be generated, but will
poke the TCP re-transmission machinary to make sure that the connection is
intact.

louie