Jacob Palme wrote:
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.
It is an argument supplied to the program when executed.
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.
That's one way. Running an external program (usually on the
same host) is another method sometimes used, particularly by
older MUAs.
Is "-t" an ESTMP facility?
No.
How, otherwise, can the MUA tell
the MTA that it wants the MTA to remove Bcc headers from
non-Bcc recipients?
By invoking the external program with the specified argument
and providing the message as input.
Of course, not everybody wants to run (much less administer
and maintain) sendmail on every host with an MUA. Nor is it
practical when run on a different host via remote execution
(user names.ids might not match, there are security implications,
etc.).