What Is a Private IP Address?

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Using a private IP address on a residential or business computer can improve network security and conserve public addressing space. What does a private IP address look like? What IP address ranges qualify as private?

An IP address is considered private if the IP number falls within one of the IP address ranges reserved for private uses by Internet standards groups. These private IP address ranges exist:

  • through through (APIPA only) through through

Private IP addresses are typically used on local networks including home, school and business LANs including airports and hotels.

Can a Private Ip Address Connect to the Internet?

Devices with private IP addresses cannot connect directly to the Internet. Likewise, computers outside the local network cannot connect directly to a device with a private IP. Instead, access to such devices must be brokered by a router or similar device that supports Network Address Translation (NAT). NAT hides the private IP numbers but can selectively transfer messages to these devices, affording a layer of security to the local network.

Standards groups created private IP addressing to prevent a shortage of public IP addresses available to Internet service providers and subscribers.

Reserved vs. Private Addresses

While private IP addresses can be used on local networks (just not the public Internet), reserved IP addresses cannot be used at all for normal network communication. is the loopback address in IP. Loopback is a test mechanism of network adapters. Messages sent to do not get delivered to the network.

Instead, the adapter intercepts all loopback messages and returns them to the sending application. IP applications often use this feature to test the behavior of their network interface. IP officially reserves the entire range from through for loopback purposes. Nodes should not use this range on the Internet, and it should not be considered part of the normal Class A range.

As with the loopback range, the address range fromĀ through should not be considered part of the normal Class A range. 0.x.x.x addresses serve no particular function in IP, but nodes attempting to use them will be unable to communicate properly on the Internet.

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