Faster SSH Logins

When logging in via SSH there is a noticeable delay before the shell is accessible. This can be due to the complex cryptographic handshaking that goes on at the start of the session. If the network is not a bottleneck, this delay will be even more noticeable on slower machines. Situations requiring many separate ssh connections suffer from this.

FSH

fsh (http://www.lysator.liu.se/fsh/) establishes a connection to the remote host and leaves it accessible for future connections. It is written in python and works reasonably well. The routebot script on the border routers uses this.

Presently it is only available in binary package form for RHEL4, some older Redhats and Debian/Ubuntu.

It has more or less been replaced by similar, better functionality in recent versions of OpenSSH.

Usage

just run fsh

OpenSSH

OpenSSH 3.9 and above (client) now has support for multiple shell channels over the same connection. Supposedly the daemon has supported it for much longer.

Edit your SSH config to include the following under Host *

# Only use these settings on a TRUSTED machine!
ControlMaster auto
ControlPath /tmp/.ssh-control-%r-%h-%p

The master session can only exit once all slave sessions have exited.