[ Thanks to An Anonymous Reader for
this link. ]
“What’s DenyHosts? It’s a small utility that blocks attempts to
connect to your server via SSH when there are too many failed
attempts or (if you enable the feature) when a host matches a
centralized list of addresses that have been making too many failed
attempts to connect via SSH.“If you’ve maintained a server for any amount of time, you’ve
probably noticed a number of failed SSH login attempts in
/var/log/secure, /var/log/messages, or /var/log/auth.log —
depending on which distro or *nix flavor you’re using. I ran into
this recently with a slew of attempts from an address that resolves
to a “.kr” domain. Since I’m relatively sure I haven’t been to
South Korea lately and I have no colleagues or friends with access
in South Korea, it’s a no-brainer that the failed attempts are
illegitimate.”