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Why are home networks prefixed with 192.168?

Why local network addresses usually are like 192.168.xxx.xxx? Is there any reason they start with 192.168 or is it just a convention?


Convention, see RFC 1918:

The Internet Assigned Numbers Authority (IANA) has reserved the following three blocks of the IP address space for private internets:        -  (10/8 prefix)      -  (172.16/12 prefix)     - (192.168/16 prefix)

Out of these blocks the is most often used as the default for home routers because it consists of 256 class C networks which all have the default netmask of The other blocks are a class A and 16 class B networks which makes them less suitable for consumer grade devices because of the different netmask required.

See also Wikipedia:Private Network which is not authoritative, but gives a nice overview.

  • Downvoted because modern hardware does not use classful addressing anymore. – kinokijuf Apr 15 '15 at 5:43
  • @kinokijuf: Funny, because this answer has no reference of hardware or classful addresing. It instead has a reference of modern IANA reservations. – Tamara Wijsman Apr 15 '15 at 7:36

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