Found that doc earlier. Do you need to forward port 25 to internal smtp server and allow in the packet filter or does the proxy take care of everything for you? I see messages getting to my firewall but they won't go on to my smtp server.
By using the SMTP proxy, you do not need set packetfilters regarding smtp by your own. All relevant filters are set automatically by your ASL. To get the smtp proxy to work: 1) point the MX record to your external interface of ASL 2) Define the allowed networks to send mail through the proxy (normally only your internal Mailserver) 3) Define your Mailserver in the routing target, that all mails are forwarded to it. 4) define special checks like using BATV, SPF ... Thats is! bagira