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---
summary: "Bonjour/mDNS discovery + debugging (Gateway beacons, clients, and common failure modes)"
read_when:
- Debugging Bonjour discovery issues on macOS/iOS
- Changing mDNS service types, TXT records, or discovery UX
title: "Bonjour discovery"
---
# Bonjour / mDNS discovery
OpenClaw uses Bonjour (mDNS / DNS‑SD) to discover an active Gateway (WebSocket endpoint).
Multicast `local.` browsing is a **LAN-only convenience**. The bundled `bonjour`
plugin owns LAN advertising and is enabled by default. For cross-network discovery,
the same beacon can also be published through a configured wide-area DNS-SD domain.
Discovery is still best-effort and does **not** replace SSH or Tailnet-based connectivity.
## Wide-area Bonjour (Unicast DNS-SD) over Tailscale
If the node and gateway are on different networks, multicast mDNS won’t cross the
boundary. You can keep the same discovery UX by switching to **unicast DNS‑SD**
("Wide‑Area Bonjour") over Tailscale.
High‑level steps:
1. Run a DNS server on the gateway host (reachable over Tailnet).
2. Publish DNS‑SD records for `_openclaw-gw._tcp` under a dedicated zone
(example: `openclaw.internal.`).
3. Configure Tailscale **split DNS** so your chosen domain resolves via that
DNS server for clients (including iOS).
OpenClaw supports any discovery domain; `openclaw.internal.` is just an example.
iOS/Android nodes browse both `local.` and your configured wide‑area domain.
### Gateway config (recommended)
```json5
{
gateway: { bind: "tailnet" }, // tailnet-only (recommended)
discovery: { wideArea: { enabled: true } }, // enables wide-area DNS-SD publishing
}
```
### One-time DNS server setup (gateway host)
```bash
openclaw dns setup --apply
```
This installs CoreDNS and configures it to:
- listen on port 53 only on the gateway’s Tailscale interfaces
- serve your chosen domain (example: `openclaw.internal.`) from `~/.openclaw/dns/<domain>.db`
Validate from a tailnet‑connected machine:
```bash
dns-sd -B _openclaw-gw._tcp openclaw.internal.
dig @<TAILNET_IPV4> -p 53 _openclaw-gw._tcp.openclaw.internal PTR +short
```
### Tailscale DNS settings
In the Tailscale admin console:
- Add a nameserver pointing at the gateway’s tailnet IP (UDP/TCP 53).
- Add split DNS so your discovery domain uses that nameserver.
Once clients accept tailnet DNS, iOS nodes and CLI discovery can browse
`_openclaw-gw._tcp` in your discovery domain without multicast.
### Gateway listener security (recommended)
The Gateway WS port (default `18789`) binds to loopback by default. For LAN/tailnet
access, bind explicitly and keep auth enabled.
For tailnet‑only setups:
- Set `gateway.bind: "tailnet"` in `~/.openclaw/openclaw.json`.
- Restart the Gateway (or restart the macOS menubar app).
## What advertises
Only the Gateway advertises `_openclaw-gw._tcp`. LAN multicast advertising is
provided by the bundled `bonjour` plugin; wide-area DNS-SD publishing remains
Gateway-owned.
## Service types
- `_openclaw-gw._tcp` — gateway transport beacon (used by macOS/iOS/Android nodes).
## TXT keys (non-secret hints)
The Gateway advertises small non‑secret hints to make UI flows convenient:
- `role=gateway`
- `displayName=<friendly name>`
- `lanHost=<hostname>.local`
- `gatewayPort=<port>` (Gateway WS + HTTP)
- `gatewayTls=1` (only when TLS is enabled)
- `gatewayTlsSha256=<sha256>` (only when TLS is enabled and fingerprint is available)
- `canvasPort=<port>` (only when the canvas host is enabled; currently the same as `gatewayPort`)
- `transport=gateway`
- `tailnetDns=<magicdns>` (mDNS full mode only, optional hint when Tailnet is available)
- `sshPort=<port>` (mDNS full mode only; wide-area DNS-SD may omit it)
- `cliPath=<path>` (mDNS full mode only; wide-area DNS-SD still writes it as a remote-install hint)
Security notes:
- Bonjour/mDNS TXT records are **unauthenticated**. Clients must not treat TXT as authoritative routing.
- Clients should route using the resolved service endpoint (SRV + A/AAAA). Treat `lanHost`, `tailnetDns`, `gatewayPort`, and `gatewayTlsSha256` as hints only.
- SSH auto-targeting should likewise use the resolved service host, not TXT-only hints.
- TLS pinning must never allow an advertised `gatewayTlsSha256` to override a previously stored pin.
- iOS/Android nodes should treat discovery-based direct connects as **TLS-only** and require explicit user confirmation before trusting a first-time fingerprint.
## Debugging on macOS
Useful built‑in tools:
- Browse instances:
```bash
dns-sd -B _openclaw-gw._tcp local.
```
- Resolve one instance (replace `<instance>`):
```bash
dns-sd -L "<instance>" _openclaw-gw._tcp local.
```
If browsing works but resolving fails, you’re usually hitting a LAN policy or
mDNS resolver issue.
## Debugging in Gateway logs
The Gateway writes a rolling log file (printed on startup as
`gateway log file: ...`). Look for `bonjour:` lines, especially:
- `bonjour: advertise failed ...`
- `bonjour: ... name conflict resolved` / `hostname conflict resolved`
- `bonjour: watchdog detected non-announced service ...`
## Debugging on iOS node
The iOS node uses `NWBrowser` to discover `_openclaw-gw._tcp`.
To capture logs:
- Settings → Gateway → Advanced → **Discovery Debug Logs**
- Settings → Gateway → Advanced → **Discovery Logs** → reproduce → **Copy**
The log includes browser state transitions and result‑set changes.
## Common failure modes
- **Bonjour doesn’t cross networks**: use Tailnet or SSH.
- **Multicast blocked**: some Wi‑Fi networks disable mDNS.
- **Sleep / interface churn**: macOS may temporarily drop mDNS results; retry.
- **Browse works but resolve fails**: keep machine names simple (avoid emojis or
punctuation), then restart the Gateway. The service instance name derives from
the host name, so overly complex names can confuse some resolvers.
## Escaped instance names (`\032`)
Bonjour/DNS‑SD often escapes bytes in service instance names as decimal `\DDD`
sequences (e.g. spaces become `\032`).
- This is normal at the protocol level.
- UIs should decode for display (iOS uses `BonjourEscapes.decode`).
## Disabling / configuration
- `openclaw plugins disable bonjour` disables LAN multicast advertising by disabling the bundled plugin.
- `openclaw plugins enable bonjour` restores the default LAN discovery plugin.
- `OPENCLAW_DISABLE_BONJOUR=1` disables LAN multicast advertising without changing plugin config; accepted truthy values are `1`, `true`, `yes`, and `on` (legacy: `OPENCLAW_DISABLE_BONJOUR`).
- `gateway.bind` in `~/.openclaw/openclaw.json` controls the Gateway bind mode.
- `OPENCLAW_SSH_PORT` overrides the SSH port when `sshPort` is advertised (legacy: `OPENCLAW_SSH_PORT`).
- `OPENCLAW_TAILNET_DNS` publishes a MagicDNS hint in TXT when mDNS full mode is enabled (legacy: `OPENCLAW_TAILNET_DNS`).
- `OPENCLAW_CLI_PATH` overrides the advertised CLI path (legacy: `OPENCLAW_CLI_PATH`).
## Related docs
- Discovery policy and transport selection: [Discovery](/gateway/discovery)
- Node pairing + approvals: [Gateway pairing](/gateway/pairing)
[Dauer der Verarbeitung: 0.14 Sekunden, vorverarbeitet 2026-04-27]