Kai Mallari's Notes'

EC - Bonjour Diagnosis

7 min read

Bonjour Diagnosis

Symptom: Capture Pilot on the iPad says “Searching for Server” or cannot discover the Image Server, even though the network is up and devices can ping each other. Root Cause: Bonjour (mDNS) service discovery is failing — the service isn’t being advertised, or multicast traffic is being blocked. Referred from: DIT Triage - iPad Disconnected, DIT Triage - Network Setup

Don't have time to diagnose? Skip straight to Manual Connection Fallback below — it bypasses Bonjour entirely and gets the iPad connected in under 60 seconds.

Diagnosis

Quick Diagnostic Commands

Run these in Terminal on the Mac (Applications > Utilities > Terminal, or press Cmd+Space and type “Terminal”):

1. Check if the Capture Pilot service is being advertised:

dns-sd -B _http._tcp

Look for a service named “Capture Pilot” or similar. If it appears → Bonjour is working on the Mac side. The problem is on the network or iPad side.

If it does NOT appear → The Image Server isn’t broadcasting. Restart it: Capture One menu > Image Server > Restart.

2. Check if the Mac can see its own Bonjour services:

dns-sd -B _captureone._tcp

This searches for Capture One-specific services.

3. Restart the Bonjour daemon:

sudo killall mDNSResponder

(Requires admin password. If you don’t have it, skip this step and go to Manual Connection Fallback below.) This forces macOS to re-register all Bonjour services. Wait 10 seconds, then restart the Image Server in Capture One.

4. Check for multicast traffic on the network:

  • If you have access to the router admin panel, check for multicast/IGMP settings. Some routers filter multicast by default, which blocks Bonjour.

Common Causes and Fixes

1. Router blocking multicast/mDNS

  • AP Isolation, Client Isolation, or IGMP Snooping can block Bonjour
  • → EC - Router Config Checklist for the full list of router settings to check

2. macOS Firewall or Local Network permission blocking the Image Server

  • macOS Sequoia (15.0+): System Settings > Privacy & Security > Local Network — Capture One must be toggled ON. This permission doesn’t exist on earlier macOS versions.
  • All versions: System Settings > Network > Firewall. If enabled, Capture One must be in the “Allow” list.
  • Quick fix: temporarily disable the firewall during the shoot. Re-enable after.

3. Bonjour advertising on the wrong network interface

  • If the Mac has both Wi-Fi and Ethernet active, Bonjour may advertise on the wrong interface
  • Fix: System Settings > Network > set service order (drag Ethernet above Wi-Fi). Or: disable Wi-Fi on the Mac entirely.

4. mDNSResponder crash or hang

  • The macOS Bonjour daemon (mDNSResponder) occasionally crashes or becomes unresponsive
  • Fix: sudo killall mDNSResponder in Terminal, then restart the Image Server

5. Multicast storm

  • Too many Bonjour services on the network (common if venue Wi-Fi is used with many Apple devices) can flood the network with multicast traffic
  • Fix: Use the DIT’s own isolated router with only DIT devices connected

6. iPad cached a stale connection

  • The iPad remembers the last server it connected to. If anything changed (IP, port, service name), the cached connection prevents discovery.
  • Fix: Force-close the Capture Pilot app (swipe up from the bottom, swipe the app away). Relaunch.

Fix

Manual Connection Fallback

If Bonjour absolutely will not work, bypass it entirely with a direct connection. You need two pieces of information: the laptop’s IP address and the port number from Capture One.

Finding the laptop’s IP address

Finding the port in Capture One

Connecting the iPad manually — Capture Pilot

Connecting the iPad manually — Live for Studio

Browser fallback (any device)

Why set a manual port

Capture One assigns a random port every time the Image Server starts when set to “auto.” If the server crashes mid-shoot and you restart it, the port changes. Every manual connection saved on the iPad now points to the wrong port. A manually assigned port (e.g., 51234) stays the same across restarts, so saved entries in the custom server list always work. To change from auto to manual: stop the server first, enter the number, restart.

Warning: A Capture One crash can sometimes reset the manual port back to “auto.” After any crash recovery, check the port in Capture Pilot tool > Mobile tab before waiting for the iPad to reconnect. If it reverted to auto, stop the server, re-enter your manual port, and restart.

Prevention

  • Use the DIT’s own router (not venue Wi-Fi) → eliminates most Bonjour issues
  • Set a fixed port number for the Image Server (don’t use “auto”)
  • Assign static IPs to all devices → EC - Router Config Checklist
  • Test Bonjour discovery during the chain test in SOP_Photographer_Handoff

Documentation

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