SSH connection reuse

It really speedup my ssh connection & never prompt passwd for second connection to same host.
Very handy to use.

Open ~/.ssh/config file (ssh client configuration file). If you need system wide settings add to /etc/ssh/ssh_config file:
$ vi ~/.ssh/config
Append following code to reuse ssh connection for all hosts:

host *
  controlmaster auto
  controlpath /tmp/ssh-%r@%h:%p

Where,

1. controlmaster auto: Set controlmaster to auto
2. controlpath /tmp/ssh-%r@%h:%p: Specify the path to the control socket used for connection sharing. In the path, ‘%h will be substituted by the target host name, %p the port, and %r by the remote login username. It is recommended that any ControlPath used for opportunistic connection sharing include at least %h, %p, and %r. This ensures that shared connections are uniquely identified.

You can also match any host in the 192.168.0.[0-9] network range with following pattern:

Host 192.168.0.?
  controlmaster auto
  controlpath /tmp/ssh-%r@%h:%p

For any host in the ".co.in" set of domains, reuse the connection:

Host *.co.in
  controlmaster auto
  controlpath /tmp/ssh-%r@%h:%p

Save and close the file. Now connect as usual,
$ ssh vivek@vpn.nixcraft.co.in
Next, time you connect again it will use connection socket /tmp/ssh-vivek@vpn.nixcraft.in:22 to speed up things. You don't have to input password or anything else. You need one connection to be active for the second to be accelerated. This also works with scp / sftp etc:
$ scp /path/to/file.txt vivek@vpn.nixcraft.co.in:/tmp

Welcome if still its not working on your machine.


You can have ~/.ssh/config file configured as
===============================================

host lin
hostname 172.16.13.20
user root
port 22

host Lin
hostname 172.16.13.20
user mahendra
port 22

host *
controlmaster auto
controlpath /tmp/ssh-%r@%h:%p

===============================================

Comments welcome !!!