External email server--configuring email-gateway, for external email server to forward email to rt in internal network

I’m sending this again because I didn’t include a subject last time. If
possible, can you please repost, so all RT users can view the subject.
Thank YOu

Linux 2.4.8-26mdk
perl5 revision 5.0 version 6 subversion 1
apache 1.3.23

I need help in figuring out how to create tickets via e-mail. My main
email server is running Lotus Notes Domino, and it is external to RT. Has
anyone got an idea for this type of configuration. Thank You