Prior to V8.12, if you were running
sendmail as a daemon, you needed to define SMTP
to enable mail transfers. If you didn't intend to
run sendmail as a daemon, SMTP did not need to
be defined. The default was that SMTP was automatically defined if
either NETINET or NETISO was defined; otherwise, SMTP was undefined.
Beginning with V8.12, the SMTP compile-time macro has been deprecated
and removed. It is now impossible to exclude SMTP support from
sendmail.
If a precompiled sendmail lacks SMTP support, an
attempt to use sendmail's
-bs command-line switch will result in this fatal
error:
I don't speak SMTP
SMTP activity can be watched with the -v
command-line switch (-v).
