How to restrict access to the server via ssh to all but a few addresses?

Question

linux

Hey!
I have vps on centos. Recently I was in a frenzy for a week and went only yesterday. And what would you think? I see - over 700 login failure attempts for root. The logs showed some kind of botnet: there are too many addresses.
I thought to block access for everyone, except for me at home and at work, but my IP address at home changes according to this principle: 14.88.10.36/37/38/39 etc. Is there a way to make a whitelist using a mask?

Answer 1

Add to /etc/ssh/sshd_config
and let them at least crack, trying to guess the password. The password for <login> must be good. And best of all - key authentication.

Answer 2

It is better to generally disable authorization by password, allow through the key. Then let them at least pick up, there will be no sense.