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A comment on Why updating DNS is slow.

Re:Why updating DNS is slow by toast0 on Sunday February 07, 2021 @08:15PM (#26059764)
Would be nice if they didn't stomp on real addresses.

> 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.

-- RFC5737 https://tools.ietf.org/html/rfc5737

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Re:Why updating DNS is slow by rubatuga on Sunday February 07, 2021 @09:02PM (#26060024)
Just wondering, how can a network block have a "2" in "192.0.2.0/24"? Shouldn't it be "192.0.0.0/24"?
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Re:Why updating DNS is slow by jlgaddis on Sunday February 07, 2021 @09:21PM (#26060124)
No, 192.0.0.0/24 and 192.0.2.0/24 are completely separate networks.

See "Classless Inter-Domain Routing" [0] (a.k.a. "CIDR")

--

[0]: https://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing

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Re:Why updating DNS is slow by Tushon on Sunday February 07, 2021 @09:08PM (#26060061)
/24 is a 256 host subnet, so you can have 1-254 (0 and 255 are special) in the last "octet" (each section of an IP address is denoted as an octet).

You can play with the numbers here [0] to see valid combos, like this: 192.1.254.19/24 (or use a 255.255.255.0 subnet mask)

0 - https://www.calculator.net/ip-subnet-calculator.html?cclass=...

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Re:Why updating DNS is slow by Craighead on Sunday February 07, 2021 @10:35PM (#26060506)
/24 means that the first 24 bits are the subnetwork mask, ie: xxxxxxxx.xxxxxxxx.xxxxxxxx.NNN, where the x represent the network and the N represent hosts on said network.

192.168.1.x/24 and 192.168.2.x/24 are two separate networks.

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Re:Why updating DNS is slow by happytoexplain on Sunday February 07, 2021 @08:29PM (#26059851)
On the other hand, there's something to be said for not using real identifiers in examples.
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