Peer discovery¶

The explorer maintains a map of network peers for the /network page. Two discovery paths:

naviod-hosted peer list — getpeerinfo reports currently-connected peers.
Direct P2P crawl — seeder-style discovery across the wider network, not limited to peers of the local node.

The second is necessary because getpeerinfo only sees ~8–125 peers. A full-chain network map needs to reach thousands.

Direct P2P crawl¶

Configurable via env vars — P2P_*, PEER_*. Overview:

Round structure¶

for round in 1..PEER_DISCOVERY_ROUNDS:
    candidates = select up to PEER_DISCOVERY_BATCH_SIZE nodes
                 from the known set, prioritising unseen / unchecked

    in parallel (P2P_CRAWL_CONCURRENCY workers):
        for candidate:
            tcp connect with PEER_CONNECT_TIMEOUT_MS
            send version message with P2P_PROTOCOL_VERSION, magic P2P_{MAIN,TEST}NET_MAGIC_HEX
            receive version + verack within P2P_REQUEST_TIMEOUT_MS
            send getaddr
            receive addr (up to 1000 addresses)
            merge new addresses into known set

    sleep PEER_DISCOVERY_WAIT_MS

Cap the total candidate set at PEER_DISCOVERY_MAX_CANDIDATES to bound memory.

Connectivity probe¶

Separate stage from the handshake crawl. After discovery:

for up to PEER_CONNECT_TEST_LIMIT peers:
    TCP connect with PEER_CONNECT_TIMEOUT_MS
    if PEER_DISCOVERY_FILTER_UNREACHABLE: drop on failure

This separates "peer exists in the address manager" from "peer is currently reachable from our vantage point".

Geolocation¶

For each new peer, look up the IP in ip-api.com with local caching. Rate-limited to PEER_GEO_LOOKUP_LIMIT uncached queries per cycle to stay within free-tier quotas. Cache hits are not counted.

The peers table stores latitude, longitude, country, city, isp — sent to the frontend for the interactive map.

Network magic¶

P2P_MAINNET_MAGIC_HEX (default bd5fc300) and P2P_TESTNET_MAGIC_HEX (default 2467d2c1). The magic bytes open every P2P message; sending the wrong magic results in the peer ignoring or banning us. Override with P2P_MESSAGE_MAGIC_HEX if a cut of testnet changes magic.

Bootstrap seeds¶

Initial candidate set for the crawl. Testnet default:

testnet.nav.io
testnet2.nav.io

Mainnet: set MAINNET_BOOTSTRAP_NODES to whatever your deployment considers authoritative (typically the same DNS seeds naviod uses).

Privacy notes¶

The crawl reveals the explorer operator's IP to every probed peer. For hidden operation, route the crawl through Tor (set P2P_PROXY=socks5://localhost:9050 — note: not implemented in the default indexer, but the pattern is straightforward to add).
The explorer publishes IP + approximate geolocation of peers. Operators who want their node invisible should run naviod with -listen=0 and connect only via outbound — such nodes will not appear in the /network map.

Tuning for a public deployment¶

Increase PEER_DISCOVERY_ROUNDS to 5–8 for more coverage at the cost of longer cycle time.
Raise P2P_CRAWL_CONCURRENCY on a high-bandwidth host.
Keep PEER_GEO_LOOKUP_LIMIT ≤ 100/min if using free ip-api; sign up for a paid plan for a production deployment.