A private IP address is an IP address reserved for internal use (in addition to public use) behind a router or other Network Address Translation (NAT) device. These contrast with public IP addresses, which are public and cannot be used within a home or business network. Sometimes, a private address is also called a local IP address.
The Internet Assigned Numbers Authority (IANA) reserves the following blocks of IP addresses for use as private IP addresses:
- 10.0.0.0 to 10.255.255.255
- 172.16.0.0 to 172.31.255.255
- 192.168.0.0 to 192.168.255.255
The first range allows over 16 million addresses, the second range allows over 1 million addresses, and the last range allows over 65,000 addresses.
Another range of private IP addresses is 169.254.0.0 to 169.254.255.255, but these are used only by Automatic Private IP Addressing (APIPA).
In 2012, IANA allocated 4 million 100.64.0.0/10 addresses for use in carrier-grade NAT environments.
Instead of using a limited supply of public IP addresses, devices within a home or business network are provided with a completely independent set of addresses that allow access to the network but do not occupy public IP address space.
For example, most routers in homes and businesses around the world have the IP address 192.168.1.1 and assign 192.168.1.2, 192.168.1.3... to various devices connected to it (using DHCP).
It doesn't matter how many routers use the 192.168.1.1 address, or how many dozens or hundreds of devices within that network share IP addresses with users of other networks, because they don't communicate directly with each other. Instead, devices on the network use routers to translate requests through a public IP address, which can communicate with other public IP addresses and ultimately other local networks.
Hardware in a specific network using a private IP address can communicate with all other hardware within the scope of that network, but requires a router to communicate with devices outside the network and then use a public IP address to communicate.
For example, before landing on this page, your device (such as a computer or phone) with a private IP address requested the page through a router with a public IP address. Once a request is made and Lifewire responds and delivers the page, the page is downloaded to your device via the public IP address and then to your router, where it is then passed to your private/local address to reach your device.
If it's easier to imagine, you can think of the entire scenario as a physical mail delivery service. To send physical mail, it must pass through smaller and larger networks to reach its destination. First, it's processed by the local post office (much like your home router), then forwarded to a larger postal service (such as the Internet) for delivery, and ultimately reaches the recipient's home. When they get back to you, everything is turned upside down.
All devices included in a private network around the world (laptops, desktops, phones, tablets, etc.) can use private IP addresses with almost no restrictions, whereas public IP addresses do not.
Private IP addresses also provide a way for devices that do not need to be connected to the Internet, such as file servers and printers, to communicate with other devices on the network without being directly exposed to the public.
Another set of IP addresses that are further restricted are called reserved IP addresses. These addresses are similar to private IP addresses in that they cannot be used to communicate on the Internet, but they are more restrictive.
The most famous reserved IP is 127.0.0.1. This address is called the loopback address and is used for testing network adapters or integrated chips. Traffic addressed to 127.0.0.1 will not be sent over the local network or the public Internet.
Technically, the entire range from 127.0.0.0 to 127.255.255.255 is reserved for loopback purposes, but in the real world you'll almost never see anything other than 127.0.0.1.
Addresses in the range 0.0.0.0 to 0.255.255.255 are also reserved, but no action is performed. If you are even able to assign an IP address in this range to a device, it will not work properly no matter where it is installed on the network.
Knowing your private IP address only helps in certain situations, and for most people, those situations are rare.
For example, if you want to use a mapped network drive to connect one computer to another computer on the network, you can do this through its local IP address. You can also control your computer remotely using a local IP address and remote desktop software. A dedicated IP address is also needed to direct a specific network port from the router to a specific computer on the same network, a process called port forwarding.
The easiest way to find a private IP address in Windows is to use the command prompt and the ipconfig command.
If you're not sure what your router or other default gateway's private IP address is, see How to Find Your Default Gateway IP Address. You can also find your public IP address, but it works slightly differently.
When a device such as a router is plugged in, it receives a public IP address from the ISP. Devices connected to the router are given private addresses.
Private IP addresses cannot communicate directly with public IP addresses. This means that if a device with a private IP address is connected directly to the Internet and therefore becomes non-routable, the device will have no network connectivity until that address is translated to a working address via NAT, or until a request for it is sent by having a valid The public IP address sent by the device.
All traffic from the Internet can interact with the router. This is true for all traffic from regular HTTP traffic to FTP and RDP. However, because the private IP address is hidden behind the router, if you want to set up an FTP server on your home network, the router must know which IP address to forward the information to. In order for private IP addresses to work properly, port forwarding must be set up.
Forwarding one or more ports to a specific private IP address requires logging into the router to access its settings, then selecting which ports to forward and where they should be forwarded.
FAQYou can use a virtual private network (VPN) service to hide your IP address. A VPN masks your actual IP address by assigning a virtual location and encrypting your personal information. Another way to hide your IP address while browsing online is to use a web proxy to create an anonymous IP address.
One option is to find the IP addresses of all devices connected to the network. You can usually find these addresses in your device settings. If you need to find the IP address of your network hardware in Windows, use the tracert command.
