Hello SJ,
To Make concepts little clear, Port 25 for Outgoing is the Standard port for Your SMTP server(managed by Exchnage Admins) and this cannot be changed.
For Incoming, Your SAP AS acts as the SMTP server and the port cane be 25 or 25000 or any other free port on server. Use 'Netstat' command at OS level of SAP server to check if the port whichyou are about to use in SAP is already been in use or not. If not Just Assign any free port as per your wish.
Afterall, You are the admin of the SAP box.
Regards,
Arun
