If you are running Domino® and Simple Mail Transfer Protocol (SMTP) on the same system, it is suggested that you configure each one to bind to a specific IP address.
When hosting Domino and SMTP servers on the same system, you should bind each server to an IP address. Mail is then sent to users of Domino or SMTP using the appropriate IP address and although it shares a port, the mail is only handled by the system for which it is intended.
To force the SMTP server to use a specific Internet address, follow these steps:
If you want to use network address translation (NAT) either on the system or on your firewall, force the i5/OS® SMTP client to use one specific Internet address.
Now, SMTP receives only mail that is addressed to this Internet address. Check the Domain Name System (DNS) server, local host table, and system distribution directory to ensure that this forced Internet address is present.
Refer to the Lotus Domino Reference Library for instructions on how to bind Domino SMTP to a specific TCP/IP address.
Related concepts
IP filtering and network address translation (NAT)