Mastering Linux Security and Hardening - Second Edition

Scanning for enabled SSH algorithms

We have two good ways to scan an SSH server. If your server is accessible via the internet, you can go to the SSHCheck site at https://sshcheck.com/.

Then, just type in either the IP address or hostname of your server. If you've changed the port from the default port 22, enter the port number as well. When the scan completes, you'll see the list of enabled algorithms, along with recommendations on which ones to either enable or disable.

If the machine that you want to scan isn't accessible from the internet, or if you would rather use a local scanning tool, you can install ssh_scan. Let's get some hands-on practice with it now. I'll explain everything as we go along.