What is the use of private ip address in Android mobile?

Solution 1:

Your mobile phone will usually have only one IP address at all times.

When you are connected using Wifi, you connect to a router which hosts a local area network using private (internal) IP addresses, thereby supplying you with an internal address.

The router itself is usually connected to the internet using a public IP, in which case you would see a private IP address (which is unique in your network) on your phone, while you'll be using the routers public IP address when surfing on the internet and visiting a "what-is-my-IP" website.

However, when you are connected to a mobile data network, most carriers supply you with a public IP address directly. There is no (intermediate) router in place, and therefore no private IP addresses either. Actually the ISP at your home does the same, but there you'd like to share the broadband connection with multiple devices, while your mobile data connection is only used by your phone.