Troubleshoot "no devices found"
Diagnostic steps when go-udap discover returns nothing
"No devices found"
When go-udap discover returns nothing, work through this checklist
in order.
Step 1: Confirm the device is powered on
The most boring cause. Plug it in, wait 30 seconds for it to come fully up, try again.
Step 2: Confirm the device is on the same network segment
UDAP discovery is broadcast-based; broadcasts don't cross routers. The device and your dev machine need to be on the same VLAN / subnet.
If the device is unconfigured (no DHCP lease), it broadcasts from
source IP 0.0.0.0 — it doesn't have a subnet yet, but it must be
physically on the same Layer-2 segment.
Step 3: Check UDP port 17784 isn't blocked
Some host firewalls block inbound UDP on non-standard ports. Test with tcpdump:
sudo tcpdump -i any -n -nn 'udp port 17784'In another terminal, run go-udap discover. You should see the
outbound broadcast (length 27) and the device's reply (length 61+).
If you see the outbound but no reply, the device isn't responding (check Step 1 and Step 2 again). If you see neither, your host firewall is dropping the outbound — find and fix it.
Step 4: On a multi-homed laptop, try --interface or --all-interfaces
If your host has Wi-Fi + Ethernet both up, default discovery only emits on the kernel's default-route NIC. If the device is on the other NIC's subnet, you'll see zero devices.