Overview[1]#
Private-Use Networks is a network that uses private IP Address space, following the standards set by RFC 1918 for Internet Protocol Version 4 (IPv4), and RFC 4193 for Internet Protocol Version 6 (IPv6).These addresses are commonly used for home, office, and enterprise Local Area Networks (LANs).
Private-Use Networks address spaces were originally defined in an effort to delay IPv4 address exhaustion, but they are also a feature of IPv6 where exhaustion is not an issue.
The Internet Engineering Task Force (IETF) has directed the Internet Assigned Numbers Authority (IANA) to reserve the following IPv4 address ranges for private networks, as published in RFC 1918:[1]
RFC 1918 name | IP Address range | number of addresses | largest CIDR block (subnet mask) | host id size | mask bits | classful description | |
---|---|---|---|---|---|---|---|
24-bit block | 10.0.0.0 – 10.255.255.255 | 16,777,216 | 10.0.0.0/8 (255.0.0.0) | 24 bits | 8 bits | single class A network | |
20-bit block | 172.16.0.0 – 172.31.255.255 | 1,048,576 | 172.16.0.0/12 (255.240.0.0) | 20 bits | 12 bits | 16 contiguous class B networks | |
16-bit block | 192.168.0.0 – 192.168.255.255 | 65,536 | 192.168.0.0/16 (255.255.0.0) | 16 bits | 16 bits | 256 contiguous class C networks | |
N-A | 100.64.0.1-100.127.255.255 | 100.64.0.0/10 | 100.64.0.0/10 (255.192.0.0) | 14 bits | 10 bits | Carrier-grade NAT |
Carrier-grade Network Address Translation#
Carrier-grade NAT (CGN) is defined in RFC 6598 allocated 100.64.0.0/10 This IP Address block should not be used either on Private-Use Networks or on the public InternetPrivate IPv6 addresses#
Private IPv6 addresses is described in Unique Local IPv6 Unicast Addresses (RFC 4193)Private-Use Networks Summary Table#
Address Block | Present Use | Reference |
---|---|---|
0.0.0.0/8 | "This" Network | RFC 1122, Section 3.2.1.3 |
10.0.0.0/8 | Private-Use Networks | RFC 1918 |
127.0.0.0/8 | Loopback | RFC 1122, Section 3.2.1.3 |
169.254.0.0/16 | Link Local | RFC 3927 |
172.16.0.0/12 | Private-Use Networks | RFC 1918 |
192.0.0.0/24 | IETF Protocol Assignments | RFC 5736 |
192.0.2.0/24 | TEST-NET-1 | RFC 5737 |
192.88.99.0/24 | 6to4 Relay Anycast | RFC 3068 |
192.168.0.0/16 | Private-Use Networks | RFC 1918 |
198.18.0.0/15 | Network Interconnect Device Benchmark Testing | RFC 2544 |
198.51.100.0/24 | TEST-NET-2 | RFC 5737 |
203.0.113.0/24 | TEST-NET-3 | RFC 5737 |
224.0.0.0/4 | Multicast | RFC 3171 |
240.0.0.0/4 | Reserved for Future Use | RFC 1112, Section 4 |
255.255.255.255/32 | Limited Broadcast | RFC 919, Section 7 RFC 922, Section 7 |
100.64.0.0/10 | Carrier-grade NAT (CGN) | RFC 6598 |
More Information#
There might be more information for this subject on one of the following:- Carrier-grade NAT
- Internet Protocol Address
- Network Address Translation
- Network Security
- RFC 1918
- Special-Use Domain Names
- Unique Local IPv6 Unicast Addresses
- [#1] - Private_network
- based on information obtained 2017-04-23-