Block 'no sender' emails
Hello
I was getting a huge amount of spam from junk email addresses ending in .us
I was happy using a rule to send it all to junk, but now the endless mail has started again but this time with no sender info, so the mails just show up as from (No Sender).
Does anyone know how I can block or route these mails too? I tried a rule but you need to put something in there..
Thanks
MacBook Air, macOS Sierra (10.12.4)