Possibly some lightning implementations scan for bitcoin nodes after which search for lightning functionality on high?
I am not conscious of any Lightning implementations that do that. The Lightning P2P community is a separate community to the Bitcoin P2P community and though Lightning nodes are required to look at the Bitcoin blockchain for counterparty cheat makes an attempt to implement Lightning’s safety mannequin this could possibly be finished by connecting to a block explorer (e.g. the Core Lightning plugin Sauron) moderately than operating a Bitcoin full node. It isn’t broadcast on the Lightning Community whether or not a Bitcoin full node is being run in parallel with that Lightning node or not and what the IP handle of that Bitcoin full node is.
To me it is smart to not open bitcoins port, however I might additionally think about that some scanners on the market scan for bitcoin nodes and upon success test the identical IP for a further lightning node.
If you’re operating a Bitcoin full node together with your Lightning node (which might usually be really useful for belief minimization) then whether or not you open the Bitcoin port (8333) is a Bitcoin associated query and never a Lightning one. Do you wish to enable inbound connections on the Bitcoin P2P layer, potential friends to message your Bitcoin full node and to be discoverable on a full node indexing service like bitnodes.io?
