Many thanks Mr. Venema. I just tried a "multi instance" solution and it works very well. The problem is when the number of IPs become very large: what if 20 IPs => 20 Postfix instances? I believe that this way is resource-consuming and can't be scalable as I'd like.
I also tried to use sender_dependent_default_transport_maps as you stated in the last message, but I cannot check against "sender envelope" (MAIL FROM) but against "account used for authentication" (the same for POP3). In fact, MAIL FROM headers are different from user/account used for smtp authentication. I have the same u...@domain.com for authenticating and sending on behalf of many FROM users (that are a variable-growing number). So my last questioni is: can I choose smtp transport based on user used for smtpd authentication? Thanks again for your help. Francesco --- Questa e-mail è priva di virus e malware perché è attiva la protezione avast! Antivirus. http://www.avast.com
