Tech tips & other words

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The network settings that make HomeKit and Matter actually work on Unifi hardware

What are the network settings that make HomeKit and Matter actually work on Unifi hardware?

If you’ve built a smart home around HomeKit, Matter, or Thread-enabled devices, you’ve likely run into this frustrating situation:

Everything pairs fine… until it doesn’t.

Lights become “No Response,” devices vanish from the Home app, AirPlay targets stop showing up, or Matter devices refuse to pair. These issues are almost never caused by the devices themselves. The real problem is network multicast handling — especially on UniFi networks.

HomeKit and Matter rely heavily on multicast discovery, and most networks don’t handle multicast correctly out of the box.

If you’re using a UDM / UDM Pro / UDR / Dream Machine SE/Dream Machine Pro Max with UniFi switches and APs, the fix is simple and extremely effective.


Recommended UniFi Network Settings

Setting Value Reason
mDNS Enabled Required for HomeKit & Matter device discovery
IGMP Snooping Disabled Prevents multicast packets from being dropped
IGMP Proxy Enabled Keeps multicast groups active across APs and switches
Spanning Tree Protocol RSTP Fast recovery from any accidental loop conditions

This combination dramatically increases reliability for HomeKit, AirPlay, Matter, and Thread accessories.

Note on LLDP / LLDP-MED

You may see LLDP or LLDP-MED mentioned in UniFi port details, especially on SFP uplinks. This is normal. UniFi switches and access points advertise LLDP by default to help identify devices and port topology. It has no impact on HomeKit, Matter, or multicast behavior, and there is nothing you need to configure. If you don’t see a toggle for LLDP in your controller, that’s expected — simply leave it as-is.


Why These Settings Matter

mDNS (Bonjour)

HomeKit devices announce their presence via multicast DNS:

“Is there a light here?”
“Yes — I’m Hue Bulb A23!”

If mDNS is off, devices can’t discover each other. It must remain enabled.

IGMP Snooping

In theory, it optimizes multicast traffic. In practice, many smart home devices:

  • Sleep to save power
  • Don’t send proper group-join updates
  • Stop receiving multicast broadcasts as a result

When IGMP Snooping is disabled, discovery traffic flows normally.

IGMP Proxy

Once Snooping is disabled, something must maintain group membership. IGMP Proxy does exactly that — especially important when:

  • You have multiple UniFi access points
  • You use HomePod or Apple TV as a Thread Border Router
  • You add Matter devices across rooms or floors

This is the key to keeping Matter devices reliably visible across the whole home.


Why This Helps Thread Networks

Thread creates a mesh network that bridges into your Wi-Fi network via devices like:

  • HomePod mini
  • Apple TV 4K with Ethernet
  • Eero 6/6E routers
  • Nanoleaf border router devices

For Matter to work consistently, multicast must be passed between Wi-Fi and Thread seamlessly. This configuration ensures that happens.


Example Network

UDM Pro ? US-24-PoE switch ? UniFi APs
                                ?
                      HomeKit / Matter Devices

With the settings above, this layout works reliably and consistently — no VLAN tricks or workarounds required.


Final Thoughts

If your smart home feels glitchy or inconsistent, it’s likely not the devices — it’s the network’s multicast handling.

Turning on mDNS, turning off IGMP Snooping, and enabling IGMP Proxy makes HomeKit and Matter devices:

  • Discover faster
  • Stay connected longer
  • Pair more reliably
  • Stop randomly dropping offline

Small change. Big improvement.

Clear Mac OS DNS cache via command line

The method for clearing or flushing the local cache in Mac OS has changed over the years. Here are all the Mac OS versions on one page that details how to clear Mac OS DNS cache via command line.

TLDR; Add this alias to your .zshrc file:

alias flushdns="sudo killall -HUP mDNSResponder;sudo killall mDNSResponderHelper;sudo dscacheutil -flushcache;say 'cache flushed' -v Tessa -r 229"

Then issue this command:

source ~/.zshrc

And now you can run this command and get nice audio confirmation:

flushdns

Clear your DNS cache on macOS Tahoe 26, macOS Sequoia 15, macOS Sonoma 14, macOS Ventura 13, macOS Monterey 12, macOS Big Sur 11, macOS 10.15 Catalina, macOS 10.14 Mojave, macOS 10.13 High Sierra, macOS 10.12 Sierra, OS X 10.11 El Capitan, OS X 10.10 Yosemite, OS X 10.9 Mavericks, OS X 10.8 Mountain Lion, OS X 10.7 Lion, OS X 10.6 Snow Leopard, and OS X 10.5 Leopard using the following Terminal commands:

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Make your Mac chime at startup again

I miss the startup chime on my MacBook Pro. Make your Mac chime on startup again!

To enable it, open up terminal and type:

sudo nvram StartupMute=%00

To disable it, either reset your parameter RAM by pressing Command-Option-P-R at startup, or in terminal type:

sudo nvram StartupMute=%01

Enable OS X Server Messages (Jabber) account login from different domain

I have various Internet services like email, web and messages running on a Mini server running OS X on a subdomain.

Often, I want services like Messages to appear to use our main dot-com address, yet actually run on our internal dot-net domain.

So, how do I configure Messages server to appear to virtually function on our dot-com, yet still reside on a sub-domain?

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