On Sat, 9 Jul 2022, Greg Wooledge wrote:
And every single piece of this discussion is irrelevant to the OP's issue, which is that their MTA is apparently not listening on 127.0.0.1;25. IPv6 is a red herring.
Yes, this is my fault for choosing an inappropriate Subject line. I will try again with, I hope, a better informed question and a better Subject.
Roger