SSH enables you to log in to a remote host securely, primarily by system administrators. The log-in process could be slow or is not fast enough for you. The slowness adds up if you need to log in many times a day remotely as part of your daily job.
There are a few ways to speed up authenticating to a remote SSH server which you can implement from both the client and server-side.
SSH server could be configured to perform a reverse DNS lookup of incoming connection which could delay the log in process.
SSH server might have to check if you're using GSSAPI authentication even if you're conecting via other authentication method.
multiplexing allows sharing and reuse of SSH connection which could significantly speed up remote SSH server access.
Related: How to use multiplexing in SSH
SSH client will try multiple authentication methods unless manually specified.
Not having to manually key in username and password during log in will speed up SSH authentication.
Related: How to SSH without password
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