sendmail, 4th Edition

SmtpGreetingMessage

The SMTP greeting message All versions

When sendmail accepts an incoming SMTP connection it sends a greeting message to the other host. This message identifies the local machine and is the first thing it sends to say it is ready.

Prior to V8.7 sendmail, this message was declared with the $e macro. Beginning with V8.7 sendmail, it is declared with the SmtpGreetingMessage option. In both cases, the message must begin with the fully qualified name of the local host. Usually, that name is stored in $j. The minimal definition for both is:

O SmtpGreetingMessage=$j   ← beginning with V8.7
De$j                       ← V8.6 and earlier

Additional information can follow the local hostname. Any additional information must be separated from the hostname by at least one space:

De$j additional information
    ↑
    at least one space

Traditionally, that additional information is the name of the listening program (in our case, always sendmail), the version of that program, and a statement that the program is ready. For example:

O SmtpGreetingMessage=$j Sendmail $v ready at $b  ← beginning with V8.7
De$j Sendmail $v ready at $b                      ← V8.6 and earlier

Note that it is not uncommon to see imaginative (and legal) variations in the additional information:

De$j Sun's sendmail.mx is set to go (at $b), let 'er rip!

Under versions V8.6 and earlier, there was no default for this greeting message. You had to define $e in every configuration file. Beginning with V8.7, sendmail checks to see whether the SmtpGreetingMessage option was ...