Standard Ssh client reads the configuration files before any connection:
/etc/ssh/ssh_config # system-wide
~/.ssh/config # per user
with the latter with more priority.
Ideally you want to configure the systemwide config with parameters that please all users and the config in your homedir with options specific to you.
Here's an expample of
Then to connect:
~/.ssh/config must have read/write permissions for the user, and not be accessible by others (
chmod 600 ~/.ssh/config)
All possible options are documented in ssh_config manual pages: man ssh_config