Why does SSH fall off?

Question

linux

Hello. There is a php script that runs rsync via passthru every day and transfers some files to different servers. Everything would be fine, but after some time (several weeks) SSH access to these servers becomes impossible (and to all, but not at the same time, some are available): rsync gives an error that it is impossible to connect. I'm trying to connect via WinScp - the same trouble. The assembly is standard, most of the default settings. Tell me, please, what logs to look at, what kind of symptom is this? Thank you.

Answer 1

does the script work on your machine? if so, can your ip be banned by fail2ban?

Answer 2

I support the idea with fail2ban.
first look in /var/log/auth - by default ssh writes there