I always try postmaster@ first, when reporting mail problems. Unfortunately, I'd guess that ~75% of the domains I try to contact about that don't have it. (And

I always try postmaster@ first, when reporting mail problems. Unfortunately, I'd guess that ~75% of the domains I try to contact about that don't have it. (And only slightly better with abuse@, for that matter.) And then there are the shops who seem to believe that sending mail from bad addresses and publishing no public email addresses for anything is cool. I'm not fond of this solution, but have started considering them spammers and blocking them entirely. (I don't particularly care about them - if they want to send email to my systems they can put their big-pants on and join the rest of the responsible operators; I just don't like seeing services balkanizing like this.)