At 20.56 +0200 04-08-17, Kai Henningsen wrote:
... when using the -t option.
I do not understand this "-t" option. "-t" looks to me like
a Unix shell command parameter. I thought that MUAs
communicated with MTAs for outgoing mail using the SMTP
protocol or a variant of SMTP adapted for communication
between an MUA or the first MTA, and not by using a
unix shell interface.
Some do, many do not. The lack of a standarized submission mechanism for most
of the time RFC822/SMTP has existed has led to a large number of ad-hoc schemes
being developed. Some are true MSA mechanisms while others actually implement a
split MUA. (And some are configurable and can do both.)
Some schemes are proprietary and only operate between one specific pair of
entities, others are more open. Submission can be done over protocol (not
necessarily TCP - I've seen DECnet, X.25, and even X.29 used), it can be done
via a subroutine library, or it can be done through a pipe. I'm sure there are
many other variants as well, and I haven't even touched on non-RFC822-based
email here.
Ned