I use an email client called Alpine. Currently I start it in one of several different modes in order to specify the outgoing SMTP server based on what I'm doing, in particular the From address that I wish to use.
What would be much more convenient is if I could simply direct Alpine to use my own SMTP server (on my laptop), which in turn would choose a relay server based on the From address of each message I'm sending.
I am hoping someone is already doing this (it seems like it should be a common need given recent tightening of restrictions on accepting mail) and that it is not complicated.
(As a bonus, I'd also like to be able to start Alpine in a mode which uses a local server that waits until Monday morning to send out messages.)
Here is possibly the same question: Changing SMTP authentication in mutt based on From e-mail address, but it is old and so are references on esmtp – I'm not sure esmtp is up to date with modern security protocols, etc.