netMon

local function getDevices(deviceType) -- This function was taken from https://github.com/sandalle/minecraft_bigreactor_control and has been modified by https://github.com/Sanwi
	local deviceName = nil
	local deviceIndex = 1
	local deviceList, deviceNames = {}, {} -- Empty array, which grows as we need
	local peripheralList = peripheral.getNames() -- Get table of connected peripherals
	for peripheralIndex = 1, #peripheralList do -- Log every device found
		if (string.lower(peripheral.getType(peripheralList[peripheralIndex])) == deviceType) then -- Log devices found which match deviceType and which device index we give them
			deviceNames[deviceIndex] = peripheralList[peripheralIndex]
			deviceList[deviceIndex] = peripheral.wrap(peripheralList[peripheralIndex])
			deviceIndex = deviceIndex + 1
		end
	end -- for peripheralIndex = 1, #peripheralList do
	return deviceList, deviceNames
end

local function listen(modem,channels)
  --Open channels
  for i=1, #channels do
    modem.setListening(channels[i],true)
  end

  --Listen
  local event, modemSide, senderID, channel, message = os.pullEvent("lan_message")

  --Close channels
  for i=1, #channels do
    modem.setListening(channels[i],false)
  end
  local channel = tonumber(channel)
  return event, modemSide, senderID, channel, message
end

channels = {101,102,103,104}
deviceList, deviceNames = getDevices("lan nic")
modem = deviceList[1]
modem.setPromiscuous(true)
while true do
  local event, modemSide, senderID, channel, message = listen(modem,channels)
  print(senderID..":"..message)
end