NIP-66: Relay Monitoring

NIP-66 defines a standard for relay monitoring events. BigBrotr implements six health tests and optionally publishes the results as Nostr events.

Six Health Tests

The Nip66 class in bigbrotr.nips.nip66 runs independent health tests, each producing a specific MetadataType:

RTT (Round-Trip Time)

Measures WebSocket latency in three phases: open (connection establishment), read (first message receipt), and write (message send acknowledgment). Each phase is timed independently. If any phase fails, subsequent phases are skipped (cascading failure).

MetadataType	`NIP66_RTT`
Measures	Open/read/write latency in milliseconds (3-phase)
Network support	All (clearnet, Tor, I2P, Lokinet)

SSL (Certificate Validation)

Inspects the relay’s SSL/TLS certificate using a two-connection methodology. Captures certificate validity, expiration date, issuer chain, Subject Alternative Names (SANs), cipher suite, protocol version, and SHA-256 fingerprint.

MetadataType	`NIP66_SSL`
Measures	Certificate validity, expiration, issuer, SANs, cipher, fingerprint
Network support	Clearnet only (overlay networks use different transport)

DNS (Resolution)

Resolves the relay’s hostname and collects DNS record types: A, AAAA, CNAME, NS, and PTR records with TTL values.

MetadataType	`NIP66_DNS`
Measures	A/AAAA/CNAME/NS/PTR records, TTL
Network support	Clearnet only

Geo (Geographic Location)

Looks up the relay’s IP address in the MaxMind GeoLite2-City database to determine geographic location, including geohash (precision 9) and timezone.

MetadataType	`NIP66_GEO`
Measures	Country, city, coordinates, timezone, geohash
Dependencies	MaxMind GeoLite2-City.mmdb
Network support	Clearnet only

Net (Network Information)

Identifies the relay’s IPv4/IPv6 addresses, Autonomous System (AS) number, organization, and network ranges.

MetadataType	`NIP66_NET`
Measures	IP addresses, ASN, organization, network ranges
Dependencies	MaxMind GeoLite2-ASN.mmdb
Network support	Clearnet only

HTTP (Headers)

Captures the Server and X-Powered-By HTTP headers from the WebSocket upgrade response using trace hooks.

MetadataType	`NIP66_HTTP`
Measures	Server header, X-Powered-By header
Network support	All

Event Publishing

When the Monitor is configured with Nostr keys, it publishes monitoring results as Nostr events:

Kind 10166 — Monitor Announcement

A replaceable event announcing the monitor’s capabilities, supported networks, and configuration. Each new publication replaces the previous one.

Kind 22456 — Ephemeral Relay Test

An ephemeral event containing individual health test results. Not stored long-term by relays.

Kind 30166 — Relay Discovery

A parameterized replaceable (addressable) event where the d tag identifies the relay. Contains aggregated health data per relay, enabling clients to subscribe to monitoring data for specific relays.

Event Structure

{
  "kind": 30166,
  "tags": [
    ["d", "wss://relay.example.com"],
    ["rtt", "45"],
    ["ssl", "valid"],
    ["dns", "resolved"]
  ],
  "content": "",
  "created_at": 1700000000
}

Events are broadcast to configured relays using broadcast_events() from bigbrotr.utils.protocol.

Error Handling

Like NIP-11, all NIP-66 test methods never raise exceptions. Each test returns a result with logs.success indicating whether the test completed successfully. Failed tests produce no metadata — they are simply logged and skipped.

GeoIP Databases

The Geo and Net tests require MaxMind GeoLite2 databases:

GeoLite2-City.mmdb — for geographic location
GeoLite2-ASN.mmdb — for network/ASN information

These are managed by the GeoReaders mixin in services/common/mixins.py, which handles database file loading and lifecycle management. Database paths are configured in the Monitor’s YAML config.