I have a PC and a Mac. My server is running on the Mac on port 3000, and I need to do test on my PC. How can I access my server from my PC which is in the same local network?
Get your Mac's IP address from Network preferences (let's say it's 192.168.1.2), then you should just be able to type
into Internet Explorer's address bar on the PC.
If you have the firewall enabled on your Mac, you'll need to ensure that whatever web server you're running on it is allowed to accept incoming connections.
Just point your browser to the Mac's IP with the right port.