this post was submitted on 25 Mar 2024
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[Outdated, please look at pinned post] Casual Conversation

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[–] dr_lobotomy@lemmynsfw.com 21 points 7 months ago (5 children)

Class A/B/C in networking. I always wondered why there were classes if you would use a subnetmask regardless.

Took me a while to realize that class notation was only used before sub netmasks were a thing. The best you could do is to ignore them completely.

Networking is a wonderful field where you think you understand it until you look at the parts and realize you had it all wrong.

[–] KnightontheSun@lemmy.world 4 points 7 months ago (4 children)

The class notation is still meaningful. If we were talking about your particular network mask I might ask you what class it is. Telling me would give an understanding of size or hops or whatever. Granted, it is class C 99% of the time. Probably smaller. But then I’m certainly no networkologist.

[–] intensely_human@lemm.ee 2 points 7 months ago (2 children)

I still don’t understand what a network mask is

[–] dr_lobotomy@lemmynsfw.com 1 points 7 months ago* (last edited 7 months ago)

Lemme try: an IP is the address of your computer and only a single number. If you want to group clients you have to define a way to separate these 32bit number into a part that defines the group and a part that defines the number of the client in that group. That's what the netmask is for. Example:

IP: 10.0.0.1

Netmask: 255.255.0.0

In binary this gets more clear:

IP: 0000 1001.0000 0000.0000 0000.0000 0001

Netmask: 1111 1111.1111 1111.0000 0000.0000 0000

The netmask is always a bunch of 1 first, then 0 until you got 32 of it. 1 define the parts of the IP that define the group, 0 the client.

10.0 is the group, 0.1 is the number of the client in our example. All clients which IP begin with 10.0 are in the same group and can talk to each other without needing a router.

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