Whenever I used ssh, I would constantly be getting warnings like this:
Warning: Permanently added 'somehost.org,188.8.131.52' (RSA) to the list of known hosts.
The warning would show up even when I was connecting to a host and IP address I’d connected to previously.
The solution was to add the following line to my ~/.ssh/config file…
(Turns out I did have a UserKnownHostsFile configuration entry, but for some reason it was set to /dev/null.)