Port 25 is used for email servers. This is because the server instance on a machine can prove to be run by an administrator. Additionally most providers don’t allow you to use port 25. Both techniques are used in order to avoid spam.
But: Chatmail is not vulnerable to spam. So couldn’t we just choose another port for a “Chatmail network”? It would be much easier to create your own server. You wouldn’t have to check all providers for allowing port 25 and check what you have to do to open it someday.
You could just take ANY provider or host it at home.
Yes, this is what I just experienced as well. VPS provider blocks outbound traffic to port 25, and you need to open a ticket with them to ask to enable/increase packets per second on port 25. I hope they will allow it.
All the relays would have to start listening on some other port, which will be doable, but not easy, and the compatibility with classical email will be completely lost. So there is a trade-off.
Chatmail relays used for censorship circumvention rely on looking like normal mailservers, but I guess not to active probing. Would offering an additional connection over an onion (Tor) or garlic (.i2p) site be a reasonable workaround? It could also circumvent this:
