From c33f3243c1c55b66135a8a155de3844351f36ae1 Mon Sep 17 00:00:00 2001 From: simon Date: Sat, 4 Aug 2001 13:05:54 +0000 Subject: [PATCH] Add description of the keepalives option git-svn-id: svn://svn.tartarus.org/sgt/putty@1166 cda61777-01e9-0310-a592-d414129be87e --- doc/config.but | 42 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) diff --git a/doc/config.but b/doc/config.but index 001ab364..c6e99b27 100644 --- a/doc/config.but +++ b/doc/config.but @@ -530,6 +530,48 @@ more than one type of connection. \S{config-keepalive} Using keepalives to prevent disconnection +If you find your sessions are closing unexpectedly (\q{Connection +reset by peer}) after they have been idle for a while, you might +want to try using this option. + +Some network routers and firewalls need keep track of all +connections through them. Usually, these firewalls will assume a +connection is dead if no data is transferred in either direction +after a certain time interval. This can cause PuTTY sessions to be +unexpectedly closed by the firewall if no traffic is seen in the +session for some time. + +The keepalive option (\q{Seconds between keepalives}) allows you to +configure PuTTY to send data through the session at regular +intervals, in a way that does not disrupt the actual terminal +session. If you find your firewall is cutting idle connections off, +you can try entering a non-zero value in this field. The value is +measured in seconds; so, for example, if your firewall cuts +connections off after ten minutes then you might want to enter 300 +seconds (5 minutes) in the box. + +Note that keepalives are not always helpful. They help if you have a +firewall which drops your connection after an idle period; but if +the network between you and the server suffers from breaks in +connectivity then keepalives can actually make things worse. If a +session is idle, and connectivity is temporarily lost between the +endpoints, but the connectivity is restored before either side tries +to send anything, then there will be no problem - neither endpoint +will notice that anything was wrong. However, if one side does send +something during the break, it will repeatedly try to re-send, and +eventually give up and abandon the connection. Then when +connectivity is restored, the other side will find that the first +side doesn't believe there is an open connection any more. +Keepalives can make this sort of problem worse, because they +increase the probability that PuTTY will attempt to send data during +a break in connectivity. Therefore, you might find they help +connection loss, or you might find they make it worse, depending on +what \e{kind} of network problems you have between you and the +server. + +Keepalives are only supported in Telnet and SSH; the Rlogin and Raw +protocols offer no way of implementing them. + \H{config-telnet} The Telnet panel The Telnet panel allows you to configure options that only apply to -- 2.11.0