Bug 443

Summary:	Ability to set KeepAlive time
Product:	Portable OpenSSH	Reporter:	Dan <danfuzz>
Component:	ssh	Assignee:	OpenSSH Bugzilla mailing list <openssh-bugs>
Status:	CLOSED WONTFIX
Severity:	normal
Priority:	P2
Version:	-current
Hardware:	All
OS:	All

Description Dan 2002-11-25 13:47:54 AEDT

I currently have to deal with a (arguably broken) firewall which likes to drop
connections that have been idle for more than a couple minutes. Unfortunately,
while ssh gives me the option of using keepalives, it doesn't give me a way to
set the keepalive time, and, since the default is 3 hours, it doesn't do me much
good.

What I'd love to see is either a KeepAliveTime option indicating a number of
seconds between keepalives if KeepAlive is "on", or make KeepAlive itself take a
number of seconds as an option.

Thanks!

-dan
danfuzz@milk.com

Comment 1 Darren Tucker 2002-11-25 14:37:54 AEDT

The "KeepAlive" option enables TCP_KEEPALIVE on the socket which uses a 
system-wide setting (normally 2 hours according to Stevens.)

There is a "Heartbeat" patch for openssh which does what you want, see
http://www.sc.isc.tohoku.ac.jp/~hgot/sources/openssh-watchdog.html

Comment 2 Dan 2002-11-25 14:54:37 AEDT

Thanks for the reference to the heartbeat patch; I'll probably be installing it
shortly.

However, I should note that at least on some systems (on mine at least), there
*is* a TCP option to change the keepalive time.

Comment 3 Damien Miller 2002-12-03 22:56:45 AEDT

You probably want ClientAliveInterval in sshd_config

Comment 4 Damien Miller 2003-01-03 14:58:09 AEDT

As mentioned, TCP keepalives are a system-wide setting. On linux you can tweak
them using "sysctl -w net.ipv4.tcp_keepalive_time=xxx" or through /proc/sys

Adding protocol-level keepalives to the client (they are already in the server)
is a separate issue (and bug).

Comment 5 Damien Miller 2004-04-14 12:24:18 AEST

Mass change of RESOLVED bugs to CLOSED