Today, one of my email on my other domain was used for spamming. That's not new and I often get 1 or 2 per day. But today, I received about 1000+ email  in 1-2 hour to that email like Mail not delivered, AutoNotify, Returned mail ....They all used the domain but with a non existent email like toto{@}mydomain.com. That email is not normally busy and so, I never had to add a filter but I did activate the junk mail filter in Thunderbird. If you ever get in that situation, you could add this in a filter when the From or Sender fields are:
  • deamon
  • postmaster
  • host-master
  • hostmaster
This is only a partial list and you may add to it. The downside is that you may get a true Returned mail if you made a mistake sending a real email . You could however make a second filter to catch the whole email used in the body of the message. What thing I can say is that a lot of people are in vacation on this Black Friday. I go a lot out of the office email  ;)
Keywords: Email