⚠️ Key Networking Requirement

Sonos discovery depends on:

• mDNS (UDP 5353 → 224.0.0.251)
• Multicast / IGMP
• Same broadcast domain (or mDNS reflector)

Step 1 — Install Required Packages

SSH into your OpenWrt router and install Avahi for mDNS reflection:

opkg update
opkg install avahi-daemon avahi-utils

Step 2 — Configure mDNS Reflector (Avahi)

Edit the Avahi configuration file:

vi /etc/avahi/avahi-daemon.conf

Set the following values:

[server]
use-ipv4=yes
use-ipv6=no

[reflector]
enable-reflector=yes

[rlimits]
rlimit-nofile=8192

Enable and start the service:

/etc/init.d/avahi-daemon enable
/etc/init.d/avahi-daemon restart

Step 3 — Verify Firewall Allows mDNS

If you are using VLANs or segmented networks, add a rule to allow mDNS:

uci add firewall rule
uci set firewall.@rule[-1].name='Allow-mDNS'
uci set firewall.@rule[-1].src='lan'
uci set firewall.@rule[-1].dest_port='5353'
uci set firewall.@rule[-1].proto='udp'
uci set firewall.@rule[-1].target='ACCEPT'
uci commit firewall
/etc/init.d/firewall restart

Also ensure:

• LAN ↔ WLAN traffic is allowed
• No multicast blocking rules are present

Step 4 — Disable WiFi Client Isolation

Check wireless configuration:

uci show wireless

If you see:

option isolate '1'

Change it to:

option isolate '0'

Reload WiFi:

wifi reload

Step 5 — Enable IGMP Snooping

Check your LAN bridge settings:

uci show network

Ensure:

option igmp_snooping '1'

If not:

uci set network.lan.igmp_snooping='1'
uci commit network
/etc/init.d/network restart

Step 6 — Setup the Sonos Era 100

1. Connect your phone to the same WiFi network
2. Install/open the Sonos app
3. Power on the Era 100
4. Select Add Product
5. Press the pairing button when prompted

Step 7 — Verify Discovery (Advanced)

From the router shell:

avahi-browse -a

You should see entries like:

_sonos._tcp

If not, multicast/mDNS is still misconfigured.

🔧 Troubleshooting

Sonos Not Found

• Check Avahi reflector
• Ensure same subnet or reflector working

Device Drops Off Network

• IGMP snooping issue
• Disable aggressive multicast filtering

Works on ISP Router but Not OpenWrt

• OpenWrt blocks multicast by default
• Review firewall + Avahi config

Guest Network Problems

• Guest isolation blocks discovery
• Use same SSID or configure reflector properly

🧠 Recommended Network Design

Simple Setup

• Sonos + phones on same LAN/SSID

Advanced Setup

• Separate VLANs (LAN / IoT)
• Use Avahi reflector
• Allow UDP 5353 + IGMP between zones

⚡ Diagnostic Commands

tcpdump -i br-lan port 5353

You should see multicast traffic if mDNS is working.