Postfix and blocked port 25

[skiwarz]

Not entirely sure if this is the right place to ask, but hopefully someone knows.
I'm trying to run my own home email server for personal use. However, my ISP decided to block incoming and outgoing connections on port 25. Most email servers ONLY connect to other servers via port 25 (no alternatives). When you send email through a client like Thunderbird or Outlook, you can connect to an smtp server via port 465 or 587, but inter-server communication only happens on port 25. So, it seems I can't simply connect via a different port. I know I could probably relay outgoing mail through my ISP's server or gmail, but what about incoming? Also, relaying implies that I'd have message size limits, which I don't want. Anyone have a solution, or have you done something like this before?
Using Gentoo with Postfix (latest version).

[eccerr0r]

Call your ISP to unblock it.

If not, change ISPs, companies like Comcast means you're SOL. There's not really not much you can do if you want to receive mail with port 25 blocked unless you rely on another machine as the mail server.

If you have a dynamic IP there's another reason to jump ISPs or ask to get a static: I have found a lot of mail servers notice you have dynamic IP and autoflag your mail as spam. They even sometimes block mail going *to* a dynamic IP for whatever reason...
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