SSH

How To Enable SSH in Linux Mint

Passwordless SSH

Troubleshooting

If you get crap like:

Warning: the ECDSA host key for '<snip>' differs from the key for the IP address '<snip>'
Offending key for IP in /home/<snip>/.ssh/known_hosts:14
Matching host key in /home/<snip>/.ssh/known_hosts:12
Are you sure you want to continue connecting (yes/no)?

or maybe:

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that a host key has just been changed.
The fingerprint for the RSA key sent by the remote host is
SHA256:'<snip>'
Please contact your system administrator.
Add correct host key in /home/user/.ssh/known_hosts to get rid of this message.
Offending RSA key in /home/user/.ssh/known_hosts:102
  remove with:
  ssh-keygen -f "/home/user/.ssh/known_hosts" -R '<snip>'
RSA host key for '<snip>' has changed and you have requested strict checking.
Host key verification failed.

when you try to ssh to a machine...

sudo ssh-keygen -f ~/.ssh/known_hosts -R HOSTIP

Messages like:

Warning: the RSA host key for '<snip>' differs from the key for the IP address '<snip>'
Offending key for IP in /home/user/.ssh/known_hosts:102
Matching host key in /home/user/.ssh/known_hosts:103
Are you sure you want to continue connecting (yes/no)? 

mean that you have an extra entry in your known_hosts file & indicates the line you want to delete...

Some SSH reference Links

• SSH Tricks
• SSH Passwordless Login Using SSH Keygen in 5 Easy Steps
• How to SSH between ESXi 6.0U2 hosts without providing a password