Re: Why do so few mail providers support Port 587?

* Nils Ketelsen:

...

What can be done to encourage universities and other mail providers with large roaming user populations to support RFC2476/Port 587?

Give a good reason. That is still the missing part.

From the MTA perspective, 25/TCP is the "you are responsible for the message" port, 587/TCP is the "I will be responsible for the message" port. In other words, the implied abuse management contracts differ significantly.

However, this is mostly theory. I'm not sure if mail providers will try to pass responsibility for spam injected on 587/TCP to the ISP from whose address space the message was submitted. (They already do so for some parts of the abuse management process, e.g. law enforcement requests.)