To ban all email addresses from certain domain names, type an at sign then the domain name (as in @hotmail.com).
I'd go with jgeoff's advice, just .ru with no *
so just ".ru" - no "@" required?
use the @, doug. I quoted what the control panel says in my quote. Do whatever it is that your control panel says to do.
I'm confused now.

If you don't know the domain name, can't really use the
@ I would think...
It MAY work in Classic using simply
.ru rather than *.ru -- one quick test and we'll know for sure.

But yeah, in Threads a simple
%@%.ru should do it.