Troubleshooting · Networking

Why your smart home devices stopped responding (and why it's probably the network).

2026-10-02 · Obsidian Audio Video · Houston

The call comes in weekly. "My Control4 system was working perfectly for three years and now nothing responds." Or: "Our Savant app can't find the host." Or: "The Crestron touchpanel just spins and says 'connecting' forever." The homeowner assumes the control system failed — that the Crestron processor died, the Control4 controller bricked, or the Savant host crashed. Nine times out of ten, the control system is fine. What failed is the network underneath it.

Here's what actually happened: someone changed the Wi-Fi router. Maybe the ISP replaced it. Maybe a family member bought a new mesh system from Best Buy and plugged it in. Maybe the old router finally died and the replacement arrived from Amazon. The new router works — the internet is fast, Netflix streams, Zoom works — but every smart home device that communicated over the network using an IP address is now invisible. The lighting keypads still work because they're on a wired bus (Cresnet, Zigbee, or Savant's lighting bus). But the touchpanels, the apps, the AV receivers, the streaming devices, the cameras — everything that talks over IP — is gone.

What is DHCP and why does it break your smart home?

DHCP (Dynamic Host Configuration Protocol) is the system that assigns IP addresses to every device on your network. When a device connects — a TV, a Control4 controller, a Crestron touchpanel, a Savant audio zone — it asks the router for an IP address. The router leases it one from its DHCP pool, typically for 24 hours. When the lease expires, the device asks to renew. If the router is the same one that issued the original lease, the device usually gets the same IP address back. Everything keeps working.

But when you replace the router, the new router has no idea what IP addresses the old router handed out. It starts fresh. The Control4 controller that was sitting at 192.168.1.50 — which every other device on the network was programmed to talk to — now gets assigned 192.168.0.108. The Savant host that was at 192.168.1.22 is now somewhere in a completely different subnet. The Crestron processor at 192.168.1.100 is now at 192.168.0.45. Every device in the system has a new address — but every other device in the system still remembers the old one. The control system is trying to talk to devices that moved overnight, and nothing can find anything.

This is the most common cause of "my smart home stopped working" calls in Houston. It's not a failed processor, a dead controller, or a software bug. It's a DHCP lease problem caused by a router swap.

The subnet problem: why your devices can't see each other

It gets worse than just new IP addresses. Most consumer routers use the 192.168.1.x subnet by default — but some use 192.168.0.x, some use 10.0.0.x, and some use 192.168.50.x. When you replace a router that used 192.168.1.x with one that uses 192.168.0.x, you've changed the entire subnet. Devices on 192.168.1.x and 192.168.0.x cannot communicate with each other at all — they're on different networks.

We see this constantly in Houston homes. A homeowner in Memorial had their AT&T router replaced with a new AT&T router — same brand, same model — but the new one was configured for 192.168.0.x instead of 192.168.1.x. Every static IP address in the Crestron system, every IP address hard-coded into the Control4 driver, every IP address programmed into the Savant host — all of them assumed 192.168.1.x. The entire automation system went dark because the ISP technician changed one subnet setting.

The fix is either reconfiguring the new router to use the old subnet (the easy way — if the router supports it) or reprogramming every device in the system with new static IP addresses (the hard way — which can take a full day on a large system).

The mDNS problem: why apps can't find your system

Bonjour, mDNS (multicast DNS), and SSDP are discovery protocols that let devices on a network find each other without knowing IP addresses in advance. The Savant app uses Bonjour to discover the Savant host. Crestron uses mDNS for device discovery. Control4's app locates the controller via broadcast. These protocols send a "who's out there?" message to the network and wait for devices to answer.

The problem: many consumer routers and mesh systems block or mishandle multicast traffic. mDNS relies on multicast — it sends packets to 224.0.0.251, a special multicast address that every device listens to. But consumer routers, especially mesh systems like Google Nest, Eero, and Orbi, frequently block multicast by default or don't properly route it between wired and wireless networks. The result: the Savant app sends a discovery request, the host doesn't hear it, and the app says "No Savant System Found."

This is why we always configure managed switches (Ubiquiti, Araknis, or Paketek) with proper IGMP snooping and multicast routing for our Houston clients. IGMP snooping ensures multicast traffic reaches the devices that need it without flooding the entire network. Without it, the discovery packets from your app never reach the control system — and without a managed switch, you can't configure IGMP snooping at all.

IP reservations: the fix that should have been there from the start

The solution to all of this is IP reservations — also called static DHCP or DHCP reservations. Instead of letting the router randomly assign IP addresses from its pool, you tell the router: "The Control4 controller's MAC address is 00:11:22:33:44:55 — always give it 192.168.1.50." The device still uses DHCP, but it always gets the same address. This means:

• If the router reboots, every device gets its correct address back.
• If a device disconnects and reconnects, it gets its correct address.
• If you replace the router, you recreate the reservations and the system works again — no reprogramming required.
• Every other device in the system can be programmed to talk to that device's fixed IP address, and it will never change.

This is standard practice in every professional installation. We configure IP reservations for every automation controller, every AV receiver, every streaming device, every touchpanel, and every network-connected device in the system. The reservation list is documented in the project file, so if the router is ever replaced, we (or any other integrator) can recreate the reservations in 15 minutes and the entire system comes back online.

When a system was installed without reservations — or when the original integrator didn't document them — a router change becomes a full-day service call. We have to connect to every device, discover its current IP address, reprogram every driver, update every touchpanel UI, and test every scene. It's expensive, it's avoidable, and it's the single most common reason a homeowner calls us thinking they need a new system when all they need is proper network configuration.

The VLAN problem: why your IoT devices take down your AV system

There's another layer to this. In a properly designed smart home network, devices are separated into VLANs — virtual networks that isolate traffic. The AV system is on its own VLAN. The IoT devices (thermostats, door locks, smart plugs) are on another. The security cameras are on a third. The guest Wi-Fi is on a fourth.

Without VLANs, every device sees every other device's traffic. A failing smart plug that's broadcasting garbage packets can flood the network and cause your Crestron touchpanel to lag. A misconfigured camera streaming 4K video can saturate the uplink and cause your Control4 audio zones to drop. A compromised IoT device (and consumer IoT devices are notoriously insecure) can scan your network and attempt to access your AV equipment, your computers, and your personal data.

Consumer routers don't support VLANs. Mesh systems don't support VLANs. This is one of the fundamental differences between a consumer network and a smart home network — and it's why every system we install in Houston includes a managed switch with VLAN configuration. The AV VLAN ensures your Dolby Atmos stream never competes with a thermostat polling for weather data. The IoT VLAN keeps your smart locks off the same network as your AV rack. The camera VLAN isolates video traffic that could otherwise saturate a consumer router's switching capacity.

The real cost of a consumer router in a smart home

Here's the math we walk clients through in Houston:

A consumer mesh system costs $300–$500. A professional network (commercial-grade router, managed PoE switch, 3–4 ceiling access points, UPS, VLAN configuration) costs $4,000–$10,000 installed. The consumer mesh seems cheaper — until the router fails and takes down a $100,000+ automation system. The service call to diagnose, reprogram, and restore every device after a router swap runs $500–$2,000 — and if the original integrator didn't document the IP assignments, it can run higher. One router failure can cost more than the entire professional network would have cost.

We've seen it in River Oaks, Memorial, The Woodlands, Sugar Land, and Bellaire. The story is always the same: "We replaced the router and now the system doesn't work." The control system didn't fail. The AV equipment didn't fail. The lighting didn't fail. What failed was the network foundation that everything else depends on — and nobody thought about it until it was too late.

How to prevent this from happening to your system

1. Use a commercial-grade router and managed switch. Ubiquiti UniFi, Araknis, or Paketek — not a consumer mesh system. These handle 500+ devices, support VLANs, and have remote management so your integrator can diagnose issues without a site visit.
2. Configure IP reservations for every device. Document the MAC address, IP address, and device name for every piece of equipment on the network. If the router is ever replaced, this list is the difference between a 15-minute fix and a full-day service call.
3. Enable IGMP snooping and multicast routing. This ensures mDNS and Bonjour discovery work reliably — so your Savant app finds the host, your Crestron touchpanel finds the processor, and your Control4 app finds the controller.
4. Separate devices into VLANs. AV on one VLAN, IoT on another, cameras on a third, guest on a fourth. A problem in one VLAN doesn't take down the others.
5. Install a UPS on the network rack. A brief power outage reboots the router, which reissues DHCP leases, which can leave devices on wrong addresses for hours. A UPS keeps the network alive through power blips — critical in Houston during thunderstorm season.
6. Call your integrator before you replace the router. If your ISP is sending a new router, or you're considering a mesh system from Best Buy, call us first. We'll document the current IP assignments, configure the new router to match, and prevent the problem entirely. This call takes 30 minutes and saves thousands.

If your smart home devices stopped responding after a router change, don't assume the control system failed. The problem is almost certainly the network — and the fix is almost certainly IP reservations, subnet matching, and multicast configuration. We fix this weekly in homes across Greater Houston. Call us or learn more about our networking solutions.

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