SSH without password and SSH tunneling setup guide

by Chandan

SSH without password and SSH tunneling setup in 3 easy steps.

1. Create ssh keys on host, or use existing keys if you have them already.

Example: 

ssh-keygen -t rsa -C "[email protected]"

2. Add host pub key to authorized keys entry to all remote hosts(remote 0, remote 1, remote 2, etc)

Example:

# a single liner sample
cat ~/.ssh/id_rsa.pub | ssh $REMOTE -t 'mkdir -p ~/.ssh; touch ~/.ssh/authorized_keys; cat >> .ssh/authorized_keys’

3. On your host VM, add remote host SSH configurations to: ~/.ssh/config

Example:

# these goes into ~/.ssh/config
Host REMOTE1
    Hostname remote1_fullpath
    IdentityFile ~/.ssh/id_rsa
    User chandan

Host REMOTE2
    Hostname remote2_fullpath
    IdentityFile ~/.ssh/id_rsa
    User chandan

Host REMOTE3
    ProxyCommand ssh REMOTE1 -W %h:%p 
    IdentityFile ~/.ssh/id_rsa

That’s it. Now you should be able to ssh to remote hosts without password.

ssh REMOTE1
ssh REMOTE2
ssh REMOTE3

And setup local port forwarding via ssh tunneling as simple as:

ssh -fNL 8080:localhost:8080 REMOTE3
ssh -fNL 8080:localhost:8080 REMOTE1

Be sure to replace chandan with your ssh user name/id.

Happy coding!