I'm trying to connect my security cameras to my iPad and it's asking for the Port #.

You won't find a port # for an iPad that I'm aware of. Typically, security camera systems have an app, which you use to gain access to the cameras. Have you looked in the App Store for an app from the maker of the security cameras. If they don't have an app, contact the maker of the cameras to get guidance on using their product with an iPad.

Then, I'd contact them directly for help. My security cameras work through the manufacturer app without any such requirement to provide a port number.