We had a problem in my company where a Domino server lost one of it's IP addresses due to a DNS issue.
The server is our outgoing SMTP gateway, so outgoing email began piling up on multiple mail servers all over the place. As a temporary fix I tried:
Creating a new connection document to our SMTP Domino server, and on the basics tab in the source server field entered "*" (ie. asterisk on it's own, no quotes), along with a hard coded secondary IP address in the "optional network address" field.
I couldn't find this documented anywhere (even in the knowledge base) so I thought I'd share it...