On 4/29/23 04:22, Carlos E. R. wrote:

Actually, I bypass my ISP's SMTP servers. I use a non-standard
port to connect to my outside smart-relay host from my MUA.
I don't run, and don't need, to run postfix or sendmail locally.

We are talking of not using an outside smart-relay host.
Nothing outside, just your home machine and the destination machine at some other home.

Pay attention.

Carlos, with all due respect, we could continue this thread
until the cows come home, and it would be fun. But remember,
this isn't the off-topic list. Why don't we just close this thread
or move it to OT. If any of the gentle readers of this list are
interested, I'm sure that Per would let them join:

offtopic@lists.opensuse.org

Regards,
Lew