I've installed server following perfect madriva 2009.1 setup. I am using also Mikrotik Dude software - this is excellent network monitor. Dude has an option to send notifications if something is wrong. The problem is that it simply sends emails on port 25 with no authentication. In postfix info.log I am receiving : mandriva dovecot: pop3-login : disconnected (no auth attemps) : rip:xxx.xxx.xxx.xxx , lip : yyy.yyy.yyy.yyy . xxx.xxx.xxx.xxx - ip address of my Dude server yyy.yyy.yyy.yyy - ip address of my Mandriva server both adreesses are local . Can I configure postfix to allow no authenticated login only from xxx.xxx.xxx.xxx ?