Your personal SSH Configuration
Motivation
If you use ssh often then always typing long host-names or even remembering IP address is tedious. This is the time when you should start creating your own .ssh/config
Where do you find configuration files?
Configuration files for system wide programs are below /etc. Since ssh has a lot of configuration files they have chosen to put them into their own directory /etc/ssh. The configuration for your ssh client is in /etc/ssh/ssh_config while the configuration for your sshd (d for daemon - the server process) is in /etc/sshd_config and they key files can also be found in that directory.
For programs that are used by users it is necessary to have a config file for each user. Per convention the programs put their configuration files in your home directory with filenames that begin with a dot. dot-files are not shown with the ls command, unless you use ls -a.
Again: since ssh has a lot of config files they use their own hidden directory. .ssh Your ssh directory might look like this:
$ ls -1 ~/.ssh authorized_keys config id_rsa id_rsa.pub known_hosts
the config file holdes the config. id_rsa is the private key if you use Public Key Encryption and id_rsa.pub is the public part. The file known_hosts holds the entries for the fingerprints of the hosts that you have already connected to and authorized_keys holds the public keys that are allowed to connect without password.