thinQmaster Virtual testing partner Adaptive practice exams that find your weak spots and drill them. Every answer explained. From $69
Enroll

thinQmaster

Find your exam

Five questions free, before you decide.

Step 1 · choose a vendor

In one of our camps? Your practice exams come with the tuition — they are on your study page already.

Networking Fundamentals · Foundational

Private IP Address

IPv4 addresses reserved by RFC 1918 for internal use: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16.

Definition

Private addresses can be reused by any organization but are not routed on the public Internet, so traffic must be translated by NAT to reach it. They conserve public IPv4 space and are used in nearly every enterprise and home LAN. RFC 6598 shared space (100.64.0.0/10) and APIPA (169.254.0.0/16) are not RFC 1918 private ranges.

Example

A home router hands out 192.168.0.x addresses to devices on the LAN.

Exam tip

172.32.0.1 is public; the private 172 block stops at 172.31.255.255.

Don't confuse it with

Related terms