[jackal@brads-mac]# ssh -o LogLevel=quiet -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no www.somehost.com date
Thu Jun 6 15:32:55 UTC 2013
How cool is that?
Completely ignores host keys. So you'll never see an error like this again:
[jackal@brads-mac]# ssh www.somehost.com
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ 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 the RSA host key has just been changed.
The fingerprint for the RSA key sent by the remote host is
90:9c:46:ab:03:1d:30:2c:5c:87:c5:c7:d9:13:5d:75.
Please contact your system administrator.
Add correct host key in /home/user/.ssh/known_hosts to get rid of this message.
Offending key in /home/user/.ssh/known_hosts:1
Password authentication is disabled to avoid man-in-the-middle attacks.
Agent forwarding is disabled to avoid man-in-the-middle attacks.
X11 forwarding is disabled to avoid man-in-the-middle attacks.
Permission denied (publickey,password,keyboard-interactive).
$
Now to make it permanent: Add the following lines to the beginning of the SSH configuration file (~/.ssh/config).
Host *.somehost.com
StrictHostKeyChecking no
UserKnownHostsFile=/dev/null
LogLevel=quiet
You can ever remove your ~/.ssh/known_hosts file as it will no longer be needed or read anymore.