> Send an auto-reply telling them they can get their mail through if they copy a code in the reply Never auto-reply to any email ever. You're only making the

> Send an auto-reply telling them they can get their mail through if they copy a code in the reply Never auto-reply to any email ever. You're only making the spam problem worse. (Plus, if you think there are not actual persons behind most Outlook/Gmail spam, I've got news for you. They will reply, and beg you for another chance, sometimes in highly emotional terms). "550 5.7.1 The recipient has set a policy that prohibits email from this sender" at the SMTP level is the only way forward here.