Usually, you will buy an IP CAM because you want to see what's happenning in your house when you are in the office, in the coffee shop, or when you are traveling around the world. So, you install the IP CAM on the ceilling of your living room or garage, and connect this IP CAM to your home network either through wired internet or WiFi.

Since most of the home network supports DHCP, the IP CAM should be easily connected to the Internet. Now, you think that you can see the video of the IP CAM. But, actually, you have not finished the installation. When you are in the office or coffee shop, if you want to see your IP CAM video, you need to know the IP address or domain name of the IP CAM. So, you need to figure out what's the meanings of these terms like DDNS, public/private IP ,virtual servers, port mapping.....etc.

After some hard works, you will give up because it's very not easy.