ssh remote server on some port other than 22 without password

Question

I am usually connecting to the remote server with

ssh user@server.com -p 11000

and then giving the password each time for user. How should I avoid entering the password each time I connect using ssh ?

Answer 1

I think I should add a bit of a narrative to the link in 9000's answer.

First, check in home to see if you have a folder named .ssh with files inside. If .ssh doesn't exist, you don't have any key set up, so you have to generate a pair using ssh-keygen (it defaults to create the keys in ~/.ssh, you can give the keys a password or not). This will give you a .pub file in ~/.ssh (mine is id_rsa.pub). The file id_rsa.pub should look like:

ssh-rsa lotsofrandomtext user@local

Second, ssh to the server, check to see if you have a file named ~/.ssh/authorized_keys, create it if it doesn't exist. Then, append the contents of the ~/.ssh/id_rsa.pub that you generated earlier in your local machine here. This might mean copying the file contents to your clipboard, then opening ~/.ssh/authorized_keys in a text editor and pasting the lines in.

You should now be able to ssh without typing the password.

Third, if you put this in ~/.ssh/config:

Host server
HostName server.com
Port 11000
User user

You will be able to ssh server (save quite a few key strokes). Thanks to cjm for the User keyword that I forgot to mention.

Answer 2

Turn to key-based authentication.

Answer 3

As a supplement to phunehehe's answer, see the Gentoo Linux Keychain Guide for a guide to keychain. keychain also uses ssh-agent. The ssh-agent daemon makes the passphrase available (it becomes unavailable when the ssh-agent daemon dies) but keychain reuses an ssh-agent between logins, and optionally prompts for passphrases each time the user logs in, to quote the guide.