Can Heroku app use different / multiple ports?

Question

Web services on Heroku typically use the PORT environment variable, but I want to run my own mail server on Heroku. So I need to expose 2 ports, preferably 110 and 25, but I can live with alternatives. Is it possible?

Answer 1

Dotcloud allows this: https://github.com/pepijndevos/Twemail

Answer 2

No, just do some quick tests against the heroku proxy server (proxy.heroku.com). I can only connect to ports 80 and 443. Being a hero, you do not provide any POP / SMTP, it does not make sense for they are afraid to open these ports.

Answer 3

User mail server? Nope.

Heroku postal services? Yes, see the "Add-On" link for cloudmailin, mailgun and sendgrid. The basic service is free (they still want your credit card and hope that you exceed the free quota).