Bitcoin P2P Protocol The wire protocol Bitcoin nodes use to gossip transactions, blocks, and peer addresses. Default port: 8333 mainnet, 18333 testnet, 18444 regtest, 38333 signet. Message frame Handshake (no encryption / BIP324 v2) Plaintext (legacy v1) Encrypted (BIP324 v2) Started in Bitcoin Core 26.0. Differentiated by initial bytes (no magic in first message → v2 encrypted). Provides confidentiality + authentication of the channel; does not authenticate identity (no keypair-based ID, only ephemeral session). Service flags Set in field of VERSION: - — serves the full chain. - — supports .…