[feat] Forwarding sent one-to-many using different incoming vs. outgoing ports to help with self-hosting

[MrPixelized]

Hello!

In Australia, Europe and the United states of America, it is quite common for ISPs to block outgoing traffic headed for port 25 on residential networks. Since port 25 is used for server-to-server communication, this makes running an email server at home impossible, which is terrible for things like net-neutrality and self-ownership of data.

Forwardemail could help address this problem, by functioning as a relay that accepts emails arriving at port 26, and then forwarding them to their destination address, port 25.

email server -> forwardemail port 26 -> destination host port 25

This way circumventing the blockage of traffic headed for port 25. Many ISPs provide their own SMTP relay servers for this, but they're often riddled with terrible reputation and are also highly shady.

By implementing something like this, forwardemail could be a FOSS alternative, which would make the service more useful for a pretty broad user base, unless it's already a feature, in which case I've simply missed it.

P.S.: Many thanks for this great service!

Edit:
There seems to be a paid-for, non-FOSS service that does this: https://www.authsmtp.com/faqs/faq-4.html
Just putting it here in case it makes the case clearer.

[niftylettuce]

We already support port forwarding Does this work for you? https://forwardemail.net/en/guides/port-25-blocked-by-isp-workaround

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On Friday, December 10, 2021, Ischa Abraham ***@***.***> wrote: Hello! In Australia, Europe and the United states of America, it is quite common for ISPs to block outgoing traffic headed for port 25 on residential networks. Since port 25 is used for server-to-server communication, this makes running an email server at home impossible, which is terrible for things like net-neutrality and self-ownership of data. Forwardemail could help address this problem, by functioning as a relay that accepts emails arriving at port 26, and then forwarding them to their destination address, port 25. email server -> forwardemail port 26 -> destination host port 25 This way circumventing the blockage of traffic headed for port 25. Many ISPs provide their own SMTP relay servers for this, but they're often riddled with terrible reputation and are also highly shady. By implementing something like this, forwardemail could be a FOSS alternative, which would make the service more useful for a pretty broad user base, *unless* it's already a feature, in which case I've simply missed it. P.S.: Many thanks for this great service! — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#260>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAD7XBJJDSEKO2WQ34SN3WDUQIRMRANCNFSM5JZP4SGQ> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>.

[MrPixelized]

As I understand it, this guide tells you how to direct incoming email to a different port on your system, in case incoming traffic on port 25 is blocked. My suggestion would allow it to work the other way around as well: forward any sent email arriving on another port, to port 25 at the destination host.

Unless I'm understanding the FAQ wrong, the solution that it provides solves another problem.

[MrPixelized]

I suppose this would be something to implement when the SMTP server is released, and doesn't fit in the current set of features for forwardemail.