Subfinder is a subdomain discovery tool that discovers valid subdomains for websites by using passive online sources. It has a simple modular architecture and is optimized for speed. subfinder is built for doing one thing only – passive subdomain enumeration, and it does that very well.
Subfinder is designed to comply with all passive sources licenses, and usage restrictions, as well as maintaining a consistently passive model to make it useful to both penetration testers and bug bounty hunters alike.
https://github.com/projectdiscovery/subfinder
To run the software using docker, first install docker on your computer. You can find instructions to install docker at
Pull the docker image with the command
docker pull projectdiscovery/subfinder:latest
To find all subdomains of a domain, run
docker run -t projectdiscovery/subfinder:latest -d DOMAIN_NAME_HERE
