When someone talks about wanting to check open ports on a computer, they usually aren't talking about physical ports, like where you might plug in a monitor or a USB stick. Instead, they're ...

A Port basically serves as an interface between your computer and the internet or other computers in the network. Every communication over the web is exchanged using these ports, so they are an ...

When you go a website with HTTP, your browser connects to port 80 on the server running the website. Visit the site securely, with HTTPS, and your browser connects to port 443 instead.

I'm writting a server program, don't know how far I'll get but I'm giving it a try. What I need to do is open a new port for each user (connection). How, programaticly, do I check if a certain ...

You could try telneting to port 139 from an outside machine. If you get anything other than an access denied, you likely have an open port.