block junk mail without a valid address or domain

[Guest]

I have been receiving junk mail that I can't filter out or block because the
sender doesn't have a valid address or domain. How can I prevent this filth
from arriving in my In Box?

 

[Brian Tillman]

I have been receiving junk mail that I can't filter out or block
because the sender doesn't have a valid address or domain. How can I
prevent this filth from arriving in my In Box?

If you can construct a rule based on some criteria in the message, probably.