Thanks for the great script!
Working without a problem in gemeente "De wolden".

Little tip for "Domoticz-on-windows" users:

Change the line in which trhe script searches for the JSON.lua file to
JSON = (loadfile "C:\\Program Files (x86)\\Domoticz\\scripts\\lua\\JSON.lua")() -- Use default ...

Change:
local tmpFile = 'C:\Program Files (x86)\Domoticz\temp/wanip.txt'
to:
local tmpFile = 'C:\\Program Files (x86)\\Domoticz\\temp\\wanip.txt'

I Write my file to a directory without spaces so if the above doesnt work try that.
local tmpFile = 'C:\\Beheer\\Domoticz_Scripts\\wanip.txt'