Beyond Akismet and my security company, there’s a gizmo here that bans individual IP addresses, or ranges thereof, without having to rewrite .htaccess for every single example. I added two more this week, and decided to take a look at the logs. Since installation, this plugin has sent 94,263 requests by known spammers and such to the bit bucket.
Single worst offender: 18.104.22.168 (6,013 attempts).
Worst network: 96.47.225.xxx (25,881 attempts).
I think it’s safe to say that no worthwhile traffic will ever come from these addresses.