I got so much spammers who want to sell their viagra orange on my forums and most of them have .ru ont heir emails.
How to block the whole country?
Implement anti-spam measures don't block traffic.
ACP > Configuration > Banning > Disallowed Email Addresses
Enter *.ru and all email address ending with .ru will be disallowed.
@Nathan Malcolm nice tip I had no idea mybb is so advanced! MyBB is awesome