# UDP Broadcast Discovery **URL:** \ **Category:** Writing Edge Drivers\ **Tags:** support\ **Created:** [November 6, 2023, 2:43am UTC](https://community.smartthings.com/t/udp-broadcast-discovery/272697 "2023-11-06T02:43:18Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![damien1](https://avatars.discourse-cdn.com/v4/letter/d/45deac/32.png) [@damien1](https://community.smartthings.com/u/damien1)\ **Post date:** [November 6, 2023, 2:43am UTC](https://community.smartthings.com/t/udp-broadcast-discovery/272697/1 "2023-11-06T02:43:18Z")
Hi Everyone. I’m attempting to write a discovery for my edge driver. The device requires a message (‘DISCOVER\r\n’) to be braodcast over UDP on port 3310. The device will then reply by broadcasting a message containing its IP address. My code below successfully send the discovery message. I can see it in Wireshark. Likewise, the device broadcasts a message response which contains its IP address. I can see that in wireshark too. But for some reason the hub never receives the response from the device. Here’s the code. ```auto local function find_device() -- UDP socket initialization local udp = socket.udp() udp:setsockname('*', 0) udp:setoption('broadcast', true) udp:settimeout(2) -- broadcasting request log.info('===== SCANNING NETWORK...') udp:sendto('DISCOVER\r\n', '255.255.255.255', 3310) -- Socket will wait 2 seconds to receive a response back. local res = udp:receive() -- close udp socket udp:close() if res ~= nil then return res end return nil end local disco = {} function disco.start(driver, opts, cons) while true do local device_res = find_device() if device_res ~= nil then log.info('===== DEVICE FOUND IN NETWORK...') end log.error('===== DEVICE NOT FOUND IN NETWORK') end end return disco ``` Any help would be appreciated. ---
**Author:** ![AlejandroPadilla](https://yyz2.discourse-cdn.com/smartthings/user_avatar/community.smartthings.com/alejandropadilla/32/175701_2.png) [@AlejandroPadilla](https://community.smartthings.com/u/AlejandroPadilla)\ **Post date:** [November 6, 2023, 7:50pm UTC](https://community.smartthings.com/t/udp-broadcast-discovery/272697/2 "2023-11-06T19:50:57Z")
Hi @damien1 Maybe the problem is in ` local res = udp:receive()` if you try `local res = udp:receivefrom()` what happens? , I was checking the tutorial and the function is different > ---
**Author:** ![damien1](https://avatars.discourse-cdn.com/v4/letter/d/45deac/32.png) [@damien1](https://community.smartthings.com/u/damien1)\ **Post date:** [November 6, 2023, 8:45pm UTC](https://community.smartthings.com/t/udp-broadcast-discovery/272697/3 "2023-11-06T20:45:28Z")
Hi @AlejandroPadilla Thanks for getting back to me with your suggestion. Unfortunetly, I got the same result. I also tried both local `socket = require 'cosock.socket'` and `local socket = require 'socket'` with no success. Any other ideas? ---
**Author:** ![AlejandroPadilla](https://yyz2.discourse-cdn.com/smartthings/user_avatar/community.smartthings.com/alejandropadilla/32/175701_2.png) [@AlejandroPadilla](https://community.smartthings.com/u/AlejandroPadilla)\ **Post date:** [November 7, 2023, 5:53pm UTC](https://community.smartthings.com/t/udp-broadcast-discovery/272697/4 "2023-11-07T17:53:25Z")
> [@damien1](#): > > My code below successfully send the discovery message. I can see it in Wireshark. Likewise, the device broadcasts a message response which contains its IP address. I can see that in wireshark too. But for some reason the hub never receives the response from the device. Mmm, let me do some tests, Could you share the response? ---
**Author:** ![damien1](https://avatars.discourse-cdn.com/v4/letter/d/45deac/32.png) [@damien1](https://community.smartthings.com/u/damien1)\ **Post date:** [November 9, 2023, 6:29am UTC](https://community.smartthings.com/t/udp-broadcast-discovery/272697/5 "2023-11-09T06:29:42Z")
That would be great, @AlejandroPadilla. Thanks! This is the response from the device as captured in wireshark: Source IP/Port: 192.168.0.16 (3310) Destination IP/Port: 255.255.255.255 (3310) Data: DISCOVER:PA-RC2-WMP-1,CC3F1D04D392,192.168.0.16,ASCII,v1.3.3,-38,WMP\_04D392,N,3 If it helps, my code can be found [here](https://github.com/damienemmerson/ST-Edge-IntesisInterface). And, the protocol specification for the device im trying to integrate is [here](https://www.intesis.com/docs/wmp-protocol-specs). Really appreciate you helping me out! ---
**Author:** ![AlejandroPadilla](https://yyz2.discourse-cdn.com/smartthings/user_avatar/community.smartthings.com/alejandropadilla/32/175701_2.png) [@AlejandroPadilla](https://community.smartthings.com/u/AlejandroPadilla)\ **Post date:** [November 9, 2023, 6:42pm UTC](https://community.smartthings.com/t/udp-broadcast-discovery/272697/6 "2023-11-09T18:42:18Z")
> [@damien1](#): > > Destination IP/Port: 255.255.255.255 (3310) Mmm I think the hub has not received the response because the device is sending the response to the broadcast address, so what happens If you change the destination? Maybe this example can help you get the hub IP: > ---
**Author:** ![damien1](https://avatars.discourse-cdn.com/v4/letter/d/45deac/32.png) [@damien1](https://community.smartthings.com/u/damien1)\ **Post date:** [November 10, 2023, 5:16am UTC](https://community.smartthings.com/t/udp-broadcast-discovery/272697/7 "2023-11-10T05:16:44Z")
Unfortunately the manufacturer of the device has specififed how the discovery works as per the devices protocol specifications: [https://www.intesis.com/docs/wmp-protocol-specs](https://www.intesis.com/docs/wmp-protocol-specs) The device will respond on the broadcast address and that cant be changed. What would the code look like for the edge driver to listen for broadcast messages on port 3310? I cant see any options in the documentation for `udp:receive()`