Talk:IP address

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Additional Reserved IPv4 Subnets Per RFC5737

The IP Address page is protected (and my English is not good enough for editing such a page) so I just like to note that there are 3 more IP addresses subnets that are reserved: https://datatracker.ietf.org/doc/rfc5737/

The blocks 192.0.2.0/24 (TEST-NET-1), 198.51.100.0/24 (TEST-NET-2), and 203.0.113.0/24 (TEST-NET-3) are provided for use in documentation and I think that this should be noted in a separate paragraph. 2A06:C701:4C05:C200:47E2:4FB4:F37A:C580 (talk) 21:35, 26 April 2024 (UTC)[reply]

Does 127.0.0.0/8 count as part of class A?

https://www.icann.org/en/system/files/files/inet-tutorial-ajm-18jun02-en.pdf (page 15) implies that it doesn't count as part of class A, and I find it hard to believe that a mistake would stay on ICANN's website for 20 years

If it does count as part of class A, a citation should definitely be added Person568 (talk) 03:17, 14 March 2025 (UTC)[reply]

The definition of class A is that the first bit (MSB) is zero (RFC790 page 2). Class B has first two bits 10, class C is 110. Looking at those bits is how computers work out the class. 127.x.x.x has a special purpose but it is class A. Your link shows some slides for a tutorial talk. A tutorial might omit 127 because they don't want to give the impression that it is available for a private network. Johnuniq (talk) 03:46, 14 March 2025 (UTC)[reply]