Multistage SSH's configuration.

Multistage ssh

In some circumstances, it was necessary to use multistage SSH.
(It is bad that "ssh port 22 Operation timed out" comes out almost on AWS.)

Preparation

• Create server1's private key.
• Create server2's private key.

Update config

Edit ssh config file.

vim ~/.ssh/config

Add the following parameters.

Host preserver
  HostName server2.com
  ForwardAgent yes
  User server2user-name 
  IdentityFile ~/.ssh/server2key
  ProxyCommand ssh -l server1user-name -i ~/.ssh/server1key -p port-number server1.com -W %h:%p

Command

ssh-add ~/.ssh/server2key
ssh preserver

Enjoy!