Private Network Address ranges

Most people will be familiilar with the RFC 1918 standard for private network addressing.

Reading through a lot of the RFC’s, they have now been superceeded with later versions.  The most current appears to be RFC6890 although badly formatted into tables.   The prior version RFC5735 has a section 4 which is much more usable.

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

For DEV, LAB and TEST networks this shows two more segments that can be used (198.51.100.0/24 and 203.0.113.0/24) along with one I have used often 192.0.2.0/24.

Its amazing how ofter I have come accross organisations not taking these into account when planning schemes.

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