From The Hacker News
Eh, those attempts are just noise anyway. Use proper pubkey auth instead of normal passwords and you’ll be fine. Any key size is probably enough to prevent successful bruteforce attacks. Anything above 2048 and there’s basically no chance for them to guess right within several years of constant trying. Most bots move along quickly as well, they try their predefined list of (common usernames) x (common passwords) and that’s it.
Install endlessh, an ssh tar pit, if you want to make their lives a little more annoying. Use a non-standard port if your OCD can’t stand the slowly filling auth attempt logs.
Yeah they’re not getting in with my current setup anyway, I just prefer to also boot the failed attempts so I’m not relying on a single layer of protection – you never know what future security leak might rear its ugly head. I did get one issue with fail2ban fixed though so it is once again properly dropping what it can, but this bot seems to be really persistent and has quite a long list of available IPs to work from.