What is this?

This is a simple hack to findout IP of your home server, if your IP isn't static and changes over time. So you can run this script on your server and retrive the IP whenever you want.

Watch this asciinema

How to install?

Install requirements using pipenv

pipenv install

How to use?

On your server:

Run the script within the virtual environment

pipenv shell
python exposer.py

Use -h switch to see more options

To lookup the ip:

mosquitto_sub -h test.mosquitto.org -t 'ipexposer/HOSTNAME'

Note: HOSTNAME is your hostname of your server

Principle of working

After run the script, it tries to connect to a MQTT broker. by default Mosquitto free broker has been used, but you can use any other MQTT broker. After connect to a broker, the script try to retrive external ip of the server (the IP that is assigned to your router). For this purpose, the script fetches this URL to findout the IP. After that, the IP is published to a topic like ipexposer/HOSTNAME, which hostname is hostname of your server.

To lookup the ip, you can simply use a MQTT client like mosquitto_sub. Just subscribe to the topic and then you can see the IP. Please note that if you're using mosquitto.org test broker, it may be a little slow because of its heavy load. The interesting point is because the script set retain flag of published message, you can see the latest IP even if the script is sopped at the moment.