BOLT 1: introduce port convention for different network

[vincenzopalazzo]

This is an opinionate change proposed where there are reasons to have a default behavior for different networks, but there are also good reasons to have not this behavior.

I found the PR on Bitcoin core bitcoin/bitcoin#23306 very good to have a good summary of pros and cons.

In addition, I think having a default port for different networks on lightning is a good thing to have because introducing some way to detect which network a lightning node is exposing with a particular URL composed by node_id@ip:port

We introduce a default behavior on c-lighting with the PR ElementsProject/lightning#4900

P.S: As plus we have already a default port for Bitcoin maintet.

Signed-off-by: Vincenzo Palazzo vincenzopalazzodev@gmail.com

[jsarenik]

Have a look at my proposed changes please.

[Roasbeef]

Fine with me, just adding a new convention really.

[vincenzopalazzo]

Thanks for the improvement guys and the feedback, sorry if I was not present at the meeting last time.

Now the PR should be ready, and the port convention try to follow the bitcoin 0.22 convention like Mainet on port X, testnet on port 1000 + X

[michaelfolkson]

Signet would be 39735

Add signet too? I know a bunch of people are using the public default signet these days instead of testnet. Agree with taking out Litecoin :)

I found the PR on Bitcoin core bitcoin/bitcoin#23306 very good to have a good summary of pros and cons.

Bitcoin Core still has default ports for these different networks, it just now (after the above linked PR) supports changing the defaults without it impacting automatic connections. I don't think there's anything in there that argues against setting default ports for various networks across say Lightning implementations.

[vincenzopalazzo]

Add signet too? I know a bunch of people are using the public default signet these days instead of testnet. Agree with taking out Litecoin :)

I'm not very familiar with the signet network. However, the only reason that I didn't add signet as network is that we can have two or more complete blockchains in on signet right? and in this case, the default port has no sense to me.

BTW I can have some missing on this reason.

I don't think there's anything in there that argues against setting default ports for various networks across say Lightning implementations.

Mh I don't follow all the conversation on bitcoin core, but the first introduction in the PR has good pro and cons to have a default port number. Like the following one

The folklore justification (eventually actually added as a comment to the codebase in bitcoin/bitcoin#20668) is that this is to prevent the Bitcoin P2P network from being leveraged to perform a DoS attack on other services, if their IP/port would get rumoured. It appears, at least the current network scale - and probably significantly larger - that the impact is very low at best (see calculations by vasild in bitcoin/bitcoin#5150 (comment) e.g.). Another possible justification would be a risk that treating different IP:port combinations separately would help perform Eclipse attacks (by an attacker rumouring their own IP with many ports). This concern is (a) no different than what is possible with IPv6 (where large ranges of IP addresses are very cheaply available), and (b) already hopefully sufficiently addressed by addrman's design (which limits access through based selected based on network groups).

And this policy has downsides too; in particular, a fixed port is easy to detect, and a very obvious sign a Bitcoin node is running there.

[michaelfolkson]

I'm not very familiar with the signet network. However, the only reason that I didn't add signet as network is that we can have two or more complete blockchains in on signet right? and in this case, the default port has no sense to me.

There is a default signet network that Core is configured to use. Of course custom signets can be set up (and are encouraged) for testing new functionality that isn't enabled on the default signet.

And this policy has downsides too; in particular, a fixed port is easy to detect, and a very obvious sign a Bitcoin node is running there.

Yeah I guess that is arguing for something stronger than merely supporting non-default ports. I still think you need to set a default. The alternative is somehow randomizing the port number or forcing the user to choose a port number rather than falling back to the default.

[vincenzopalazzo]

There is a default signet network that Core is configured to use. Of course custom signets can be set up (and are encouraged) for testing new functionality that isn't enabled on the default signet.

Oh cool, so if there is a default signet, we can add a default port for signet! Thanks to point me out this feature.

Yeah I guess that is arguing for something stronger than merely supporting non-default ports. I still think you need to set a default. The alternative is somehow randomizing the port number or forcing the user to choose a port number rather than falling back to the default.

Yes, I agree, I think that the point of view is both correct, but lightning has some convention as in this case can be good.

[michaelfolkson]

After addressing the grammatical nit I'll ACK

[michaelfolkson]

ACK 9101f33

[Roasbeef]

LGTM ⛱

[ProofOfKeags]

I wanted to ask about the idea of LN being chain agnostic. I don't think having a single node running mainnet and testnet in the same node will be a desired use case, but my understanding was that since we have the chain id in a lot of the peer messages, it seems the original design permits different networks to share the same port.

Do we want to limit the scope of what new networks would be added?
Do we want to specify how to tell the difference between what new networks (not specified in this PR) would warrant separate ports vs just having different chain ids?

[vincenzopalazzo]

Do we want to limit the scope of what new networks would be added?
&&
Do we want to specify how to tell the difference between what new networks (not specified in this PR) would warrant separate ports vs just having different chain ids?

This PR doesn't introduce any type of scope limits, but only a standard between ports, if tomorrow's lightning network will support CatCoin we can standardize the port or you can be free to announce a new port.

You are introducing a limit if in the init message will specify MUST be chain hash of bitcoin, otherwise fails the connection

Again, this PR suggests only a standard between port numbers

[Roasbeef]

LGTM 🐅

[rustyrussell]

Ack