mvrckla is a automated tool that looks up hostnames and you can see if that address is online on a specific port
python3 mvrckla.py example.com
python3 mvrckla.py 127.0.0.1
python3 mvrckla.py sub.example.com
git clone https://github.com/adaminit/mvrckla
cd ./mvrckla/
pip install -r requirements.txt
me.