IANA-registered port number for XRP Ledger

[nbougalis]

After a conversation in #2931, I set out to get an IANA-registered port number for XRP Ledger to user. Working together with @JoelKatz, I'm happy to announce that we now have port 2459, which shall henceforth be given the official name service name xrpl:

https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=2459

So the question is, how should we move forward? Should the new default configuration file migrate from 51235 to 2459?

The change would complicate things a little bit but I don't expect it to be a breaking change, and nothing stops servers from listening on multiple ports anyways.

[mDuo13]

Tentatively, I think changing the default config file to use 2459 is a good idea, and Ripple can start configuring public servers to use 2459 in addition to 51235 probably whenever. I'll have to update the documentation to clarify that the default port has changed but that's not a huge deal.

[movitto]

@nbougalis @mDuo13 would the idea be 2459 is now the official port and 51235 is still being listened on (for the time being) but is now legacy / deprecated?

[nbougalis]

@movitto that would be my preference, since 2459 is now "officially" ours. Whether it sees adoption from server operators is another question.

[alloynetworks]

Ports are explicitly mentioned in the bootstrap hub code. Are there any other places (other than config)? How will this be handled?

[mDuo13]

Weirdly, I discovered today that the default port for the connect method is 6561 which is neither of the ones commonly in use.

So we should probably update that as part of this process.

[nbougalis]

Err, what? Yes, we absolutely should. Thanks @mDuo13!

[scottschurr]

Looking in the source code I see that the DEFAULT_PEER_PORT is now 2459. So, @nbougalis and @mDuo13, it looks like everything that we want to do regarding this issue has been done. Are we good to close this now?

[mDuo13]

We might want to change the default config file at some point so it doesn't override this with 51235. Not really sure how much of a breaking change that would be, realistically, though.

[intelliot]

Good First Issue: It may be enough to just open a PR for this one-line change - https://github.com/XRPLF/rippled/pull/4394/files#diff-2cf5913eec5c19115ee73292dcc23398439893b5f06e1f202c33cb3f3430085bL1620-R1620