On Tue, Oct 30, 2001 at 06:42:44PM -0500, KaTT KaTT wrote: > Simple high level explanation: > > 10.0.0.0/8 (255.255.255.0) is a class A addressing space > 172.16.0.0/12 (255.240.0.0) is a class B addressing space > 192.168.0.0/16 (255.255.255.0) is a class C addressing space > > All of the above are considered PUBLIC ip addresses, they are NOT routed > across the internet and should never be. Professionals get confused about > PRIVATE verse PUBLIC. PUBLIC are not routed, PRIVATE are bought through the > InterNIC (or other companies that sell IP addresses like IBM for example) > and therefor are routable.
Very good explaination overall, except you got that backwards. RFC1918 defines those three address ranges are "private". The term "private" means the addresses are only valid within a single, private entity. Public addresses are purchased from an ISP, a RR, or IANA directly. They are "public" because they are visible and valid throughout the entire public internet. ftp://ftp.isi.edu/in-notes/rfc1918.txt: The Internet Assigned Numbers Authority (IANA) has reserved the following three blocks of the IP address space for private internets: 10.0.0.0 - 10.255.255.255 (10/8 prefix) 172.16.0.0 - 172.31.255.255 (172.16/12 prefix) 192.168.0.0 - 192.168.255.255 (192.168/16 prefix) Oh, and no one uses "class A/B/C" anymore, it's passe ;) --K
