Using a log monitoring tool I had noticed an IP had attempted 100-200 logins as root though failed (PAM's logs caught that), those IPs differ slightly but originate to one single domain which is a dedicated server host somewhere which I do not care if I block access, no loss.
(EDIT: Or maybe an IP range if DNS resolution is not done during checking.. I do not know how to do that either.)
I added the IPs to my iptables, how would I block a whole host (foobar.com) from accessing any of the services on my VPS including SSH? I am using Ubuntu 10.04LTS Server.