What Is a Private IP Address?

Within each home or business network, devices connect to the Internet, and they also connect to each other. They do this through IP addresses and IP address communication. When it comes to connectivity between devices, private IP addresses within the three private IP address ranges are what keeps connections working.

What is a private IP address?

A private IP address is an IP address that is assigned to devices on private networks. These types of IPs, also referred to as local IP addresses are used on local area networks like your WiFi or a company network. These blocks of IP address have been allocated by the Internet Assigned Numbers Authority (IANA).

There are two types of IP address: IPv4 and IPv6. Originally, private IP addresses were created in order to help delay the exhaustion of IPv4 addresses, as there is a limited number of IPv4 addresses; even with the theoretical 4,294,967,296 addresses created by the 32-bit system, IPv4 address space began to run low with the amount of new Internet-connected devices that came into businesses and homes. Thus, private IP addresses allowed private networks to use the same IP addresses internally without causing conflicts for public IP addresses.

For example, thousands of WiFi routers use internal IP addresses. Networks are able to do this without conflicting because the router creates a private network, preventing external users from seeing the internal IP addresses assigned.

There are several common internal IP addresses used for home networks and routers: 192.168.1.1, 192.168.0.1, 192.168.1.254, and 10.0.0.1.

The router also assigns local IP addresses to devices on a network that connect to the WiFi. When a connected device makes a request to a website, the router directs the traffic accordingly both externally through your Internet service connection and internally back to the device that made the request via Network Address Translation (NAT).

What are public and private IP addresses?

Both public and private IP addresses are crucial to our everyday technology use. A private IP address is not directly connected to the Internet. However, it allows you to connect securely to multiple devices in your local area network. A public IP address is the IP address that connects your network to the Internet (the wide area network, or WAN) and allows local IP address to receive Internet traffic via a router.

What are the three private IP address ranges?

The three private address ranges are divided into classes. The class A private IP address range goes from 10.0.0.1 to 10.255.255.255. The class B private IP address range includes from 172.16.0.0 to 172.31.255.255, and class C private IP addresses span between 192.168.0.0 and 192.168.255.255.

Class A IP addresses

Class A has a total of 16,777,216 IPs available and is for very large networks or several networks behind the same external IP requires separation.  The typical subnet mask for this range is 255.0.0.0.

Take this scenario, for example: the network administrator wants to segment out each floor of a building where the entire building uses a single external Internet connection. The administrator doesn't want each floor to connect with devices from another floor. The solution may look like this:

All devices on floor 1 get an IP in the range of 10.1.0.*. Floor 2 IPs would be assigned 10.2.0.*, Floor 3 would be assigned 10.3.0.*. The subnet mask to keep every floor separated could be 255.255.0.0.

In simple terms, the subnet means the first two octets must match in order to communicate directly between two devices. Two devices with 10.2.0.2 and 10.2.0.3 would be able to connect directly, like a network PC and a network printer. However, a device with 10.3.0.5 would not be able to print to the same printer as devices on floor 2.

Larger networks and subnets can be very complex. The above is a very simple explanation so as not to overcomplicate an example.

Class B IP addresses

Class B has a total of 1,048,576 IPs available and is for large networks. The typical subnet mask for this range is 255.240.0.0. This is the least-used range, likely because Class A or Class C IPs will fulfill network requirements and are much easier to remember.

Class C IP addresses

Class C has a total of 65,536 IPs available. It is sufficient for most users and some businesses for their local network needs. The typical subnet mask for this range is 255.255.0.0, but most users in this network range will see the subnet as 255.255.255.0 giving that range 256 available device connections.

IPv6 addresses have been assigned the fc00::/7 range for private networks. The number of available IPv6 addresses is so vast requiring the reservation of a single address. The mindset is that there are enough IPv6 addresses that every connected advice could have an external IP address and configured in such a way to still be able to communicate within a local network.

Is 192.168 a private IP address?

Yes. This is the most common private range. Many routers use this range and come preset from the factory. If you've taken a look at local IP addresses within your own network, you've likely seen the following:
IP: 192.168.1.14
Subnet Mask: 255.255.255.0
Router or Gateway: 192.168.1.1

This is a good private IP address example; it shows all the information necessary for users.

What is a 172 IP address?

An IP that starts with 172 could be public or private. If the second octet in the IP is 16 or 31, it's definitely a private address. 172.16.1.1 and 172.31.99.4 are private, but 172.15.1.1 and 172.32.5.8 are available as a public IP address because they're outside of the designated Class B private range.

What is my own private IP?

You can easily find your local IP within your network. Web browsers, by default, previously allowed your internal IP address detection and displayed on websites like this one. However, with tightening measures in WebRTC, this is no longer allowed. Therefore, users looking to find their local or private IP must do it through their computer's operating system or command prompt system.

Find local IP in MacOS

1. Select the Apple Menu
2. Select System Preferences
3. Select Network
4. With WiFi selected in the left column, select Advanced in the lower right
5. Select the TCP/IP tab

Find local IP in Windows

1. Click Start and Select Settings
2. Choose Network & Internet from the left menu
3. Click Properties from the top menu
OR
1. Open the Start menu and type CMD and press enter
2. In the Command Prompt window type ipconfig and press enter

Find local IP in iPhone or iPad

1. Select Settings
2. Select WiFi
3. Select the information icon next to the WiFi connection

Find local IP in Android

1. Select Settings
2. Select About Phone
3. Select Status Information