---
id: 1c76d0b9-c94a-44ae-af52-372eb94ebedd
type: solution
title: "Matter commissioning requires same-subnet connectivity"
tags: [home-assistant, matter, thread, networking, proxmox, troubleshooting]
importance: 0.9
confidence: 0.8
created: "2026-01-09T06:55:57.244262+00:00"
updated: "2026-01-09T06:55:57.244262+00:00"
---

Home Assistant Matter Server must be on the same subnet as IoT devices for mDNS discovery and commissioning to work. If HA is on a server VLAN (10.10.0.x) and devices on home network (10.0.0.x), commissioning fails with 'Discovery timed out' errors. Solution: Add second NIC to VM on IoT network and make it net0 (primary) since Matter Server auto-selects first interface. Proxmox config: net0 on vmbr1 (home), net1 on vmbr0 (server).