A step-by-step guide for enabling multicast DNS in UniFi for AirPlay, HomeKit, Chromecast, and more.
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Multicast DNS (mDNS) is essential for smart home and media devices that rely on service discovery, especially when those devices exist across separate VLANs. In UniFi, enabling mDNS correctly allows devices like iPhones, printers, Chromecast, and HomeKit accessories to communicate seamlessly—even across segmented networks.
This guide explains how mDNS works in UniFi, how to enable it, and how to fine-tune mDNS proxy settings for specific services.
What Is mDNS and Why Does It Matter?
mDNS (Multicast DNS) allows devices on a local network to discover services on other devices without needing a DNS server. It’s widely used for:
- Apple AirPlay
- Google Chromecast
- Apple HomeKit
- Matter protocol
- Smart printers, speakers, TVs, and more
In a VLAN-segmented network, devices on one VLAN (like an IoT VLAN) may not be able to discover services on another VLAN without mDNS proxying.
What Devices in UniFi Support mDNS?
To use mDNS and mDNS proxy features in UniFi, you’ll need one of the following:
- UniFi Security Gateway (USG)
- UniFi Dream Machine / UDM Pro / UDM SE
- UniFi Next-Gen Gateway (UXG Pro)
📌 Some mDNS functionality may vary depending on the firmware version and gateway type.
How to Enable mDNS in UniFi Network
- Log in to your UniFi Controller
Open the UniFi Network application from your Cloud Key, UDM, or web-hosted controller. - Go to Settings → Networks
- Choose the network or VLAN where you want mDNS enabled.
- Scroll down to mDNS and toggle it ON
- Repeat for each VLAN that needs mDNS traffic enabled
🎯 Only enable mDNS on networks that include compatible devices. For example, you likely don’t want mDNS enabled on a guest or management VLAN.
How to Enable and Customize mDNS Proxy in UniFi
Recent versions of UniFi let you control what kinds of mDNS traffic are forwarded across VLANs. This is helpful for isolating your IoT devices while still allowing specific services like AirPlay or HomeKit to work.
Steps to Enable mDNS Proxy:
- Go to Settings → Networks
- Scroll down to the mDNS Proxy section
- Choose one of the following modes:
- All: Allow all mDNS traffic
- Auto: UniFi automatically determines needed services
- Custom: You select exactly which services are allowed
- To specify services, choose Custom, then click Select Services
- In the sidebar, check only the services you want to forward (e.g., AirPlay, Matter, Google Cast)
🛡️ Tip: This provides security and performance benefits by only allowing essential mDNS services across VLANs.
Use Case Example: HomeKit + IoT VLAN
If your HomeKit hub (like an iPad or Apple TV) is on your main network and your smart plugs are on an IoT VLAN, enabling mDNS proxy between those two VLANs—and allowing only HomeKit traffic—ensures everything works without exposing your entire network.
Final Recommendations
- ✅ Enable mDNS only where needed (IoT, smart home, AV networks)
- ✅ Use Custom mDNS Proxy settings to limit broadcast traffic
- ✅ Keep UniFi firmware updated to access the latest mDNS features
- ✅ Test connectivity with AirPlay or Matter devices to confirm setup
Summary: UniFi mDNS Setup Steps
| Task | Action |
|---|---|
| Enable mDNS per VLAN | Settings → Networks → Toggle mDNS ON |
| Enable mDNS Proxy | Settings → Networks → mDNS Proxy section |
| Choose allowed services | Select Custom → Select Services |
| Recommended for | AirPlay, Chromecast, HomeKit, printers, Matter |
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