On Tue, 26 Nov 2024 11:30:27 -0800 "Greg A. Woods" <wo...@planix.ca> wrote:
> One can do email submission directly to port#25 using plain (and/or > enhanced) SMTP, but the separation of concerns for various networking > policies one may need to implement make it much easier to use a separate > port. OK thanks. This is pretty much what many articles on the Internet tend to say, with heavy emphasis on ISPs trying to block spam on port 25, as the main reason. I have several books on Postfix but they were published 20 years ago and I think at that time everything was done on port 25. It is surprisingly difficult to find newly published books on email architecture. I found this one recently: https://www.tiltedwindmillpress.com/product/ryoms-ebook/
