So once in a while I’ll run into a problem where I can log into a server via SSH as one user via public key, and taking the authorized_keys keys and dumping it into another user’s .ssh/ folder doesn’t work.

There are a few things you can try.

Permissions

Try this:

chmod 0700 .ssh/
chmod 0600 .ssh/authorized_keys
sudo chown -R myuser:mygroup .ssh/

That should fix it 99% of the time.

Locked account

Tonight I had an issue where the permissions were all perfect…checked, double checked, and yes they were fine.

So after poking at it for an hour (instead of smartly checking the logs) I decided to check the logs. I saw this error:

Nov 23 05:26:46 localhost sshd[1146]: User deploy not allowed because account is locked
Nov 23 05:26:46 localhost sshd[1146]: input_userauth_request: invalid user deploy [preauth]

Huh? I looked it up, and apparently an account can become locked if its password is too short or insecure. So I did

sudo passwd deploy

Changed the password to something longer, and it worked!

Have any more tips on fixing SSH login issues? Let us know in the comments below.

There are probably a billion guides for this already, but whatever. If you DON'T have a ~/.bash_profile (a file that gets executed every time you start cyg):

touch ~/.bash_profile
chmod a+x ~/.bash_profile

Now that you have the file, add this to it:

SSHAGENT=/usr/bin/ssh-agent
SSHAGENTARGS="-s"
if [ -z "$SSH_AUTH_SOCK" -a -x "$SSHAGENT" ]; then
	eval `$SSHAGENT $SSHAGENTARGS`
	trap "kill $SSH_AGENT_PID" 0
fi

This will start up ssh-agent for each Cygwin shell you have open. Close your Cygwin shell (if one is open) and open a new one. Now type:

ssh-add ~/.ssh/id_rsa
[enter your password]

Voila! No more typing your stupid password every time you need to ssh somewhere. Note that if you close the Cygwin window, you'll have to ssh-add your key again! This is good security...you can close the window when you're done and someone who happens on your computer sitting there won't have password-less access to any of your secure logins.