A client of mine (onto my mail server) receive back some bounces for mails that he haven't never sended to non-existent addresses. Of course, inspecting the header, the outgoing server isn't mine.
I know that I can implement DKIM and SPF for help receiver server "discard" (ie.: spam folder) unwanted mails, but how can I prevent my clients to have back those bounces?
I need bounces as I want to notice my users if some mails "get lost". We run postifx on CentOS server, but I suppose the solution should be a "general" one