Sendmail X: Message Submission Programs

sendmail X.0 is intended to be used as a secure and efficient mail gateway. The current version of sendmail X does not provide a mail submission program. The documentation describes some programs that can be used for these purposes. Here is a brief (but incomplete) list of possible mail submission programs:

• sendmail 8 mail submission program. This is explained in the documentation. If you are upgrading from sendmail 8 to sendmail X then it is easy to keep the sendmail 8 mail submission program around.
• msmtp
• esmtp
• nbsmtp