On 2023-11-02 00:18, AVI GROSS via Python-list wrote:
Yes, it would be nice if there was a syntax for sending a test message sort of like an ACK that is not delivered to the recipient but merely results in some status being sent back such as DELIVERABLE or NO SUCH USER or even MAILBOX FULL.
It used to do that. The facility was very quickly turned off.
I note earlier iterations of email had addressed like mach1!mach2!mach3!ihnp4!mach5!mach6!user or even mach1!mach2!user@mach3 and I remember tools that analyzed what other machines various machines claimed to have a direct connection to and tried to figure out a connection from your source to destination, perhaps a shorter one or maybe a less expensive one. Hence machines like ihnp4 and various universities that were densely connected to others got lots of traffic. In that scenario, validity had another meaning.
Yep. It's called UUCP. It still exists. You can even do UUCP over TCP/IP. -- D'Arcy J.M. Cain System Administrator, Vex.Net http://www.Vex.Net/ IM:da...@vex.net VoIP: sip:da...@vex.net -- https://mail.python.org/mailman/listinfo/python-list
