Sendmail-TLS is a wrapper for Sendmail which allows for clients to make a secure (SSL) connection to their mailserver as described in RFC 2487. The connection is internally forwarded to sendmail and does not require sendmail to be running on port 25. Clients which support this currently are Netscape Messenger, Microsoft Outlook, and Microsoft Outlook Express.
2a10a30ecef2a314d2a15e94af90b86be8b60f222a2361a8737090b8db73b91a