From ffe78235ac99bbe8e595a376c3cfda44eb6e2bbc Mon Sep 17 00:00:00 2001 From: Michael Schmoock Date: Mon, 27 Sep 2021 13:59:10 +0200 Subject: [PATCH] BOLT 1: adds remote address to optional init_tlvs This adds the option to report an remote IP address back to a connecting peer using the `init` message. A node can decide to use that information to discover a potential update to its public IPv4 address (NAT) and use that for a `node_announcement` update message containing the new address. The proposal includes reporting the IPv4 and IPv6 address, however in IPv6 there are likely no NAT issues. TOR is skipped for obvious reasons. Certain approaches to check and use this information are thinkable: - Wait for multiple peers or a certain fraction to report the same new address. - Check some random node known via gossip to also report the new address. - Verify this information by making a test connection to itself. --- 01-messaging.md | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/01-messaging.md b/01-messaging.md index 678393e1b..2562856e6 100644 --- a/01-messaging.md +++ b/01-messaging.md @@ -259,8 +259,12 @@ The `features` field MUST be padded to bytes with 0s. 2. data: * [`...*chain_hash`:`chains`] + 1. type: 3 (`remote_addr`) + 2. data: + * `address descriptor` (1 byte type and data, see BOLT 7) The optional `networks` indicates the chains the node is interested in. +The optional `remote_addr` can be used to circumvent NAT issues. #### Requirements @@ -271,6 +275,9 @@ The sending node: - SHOULD NOT set features greater than 13 in `globalfeatures`. - SHOULD use the minimum length required to represent the `features` field. - SHOULD set `networks` to all chains it will gossip or open channels for. + - SHOULD set `remote_addr` to reflect the public IP address of an incoming + connection, if the node is the receiver and the connection was done via IP. + IP addresses that are within private networks (RFC-1918) must not be used. The receiving node: - MUST wait to receive `init` before sending any other messages. @@ -284,6 +291,7 @@ The receiving node: - MAY fail the connection. - if the feature vector does not set all known, transitive dependencies: - MUST fail the connection. + - MAY use the `remote_addr` to update its `node_annoucement` #### Rationale