I haven’t felt that way very much since leaving school for the working world, but CIDR notation is making me feel that way again for the first time in a long time. CIDR notation is basically a way of describing IP ranges and also figuring out their broadcast and subnet masks. I’ve spent a few hours today trying to figure this out and all I’ve accomplished so far is a battle to keep myself from going outside to find that old friend the two by four.

In case you’re wondering, no, I’ve never actually broken a two by four in half out of frustration. It sure SOUNDS like a fun way to work it out though.

Here’s my real problem: The best way I can wrap my head around something is to know WHY it exists in the first place. What is it there for? What is the purpose? I understand how IP addresses work in the basic sense, which is why the complicated CIDR setup seems completely pointless to me. All IPs, unless you’re inside a network using NAT, are unique. So it really seems to me like someone created this entire system as a lazy way of distributing IP ranges. How hard is it to say, for example, 69.200.100.10 – 69.200.100.15? Why does there need to be this huge complex system?

Bueller?

All I’m getting so far is “it works this way because this other part means or does such and such” but what I need to know is WHY it’s necessary for that “such and such” to be happening in the first place.

Considering DNS is supposed to have roots in math, statements like this one drive me crazy:

indicating prefix length with a suffix

It’s either a prefix or a suffix, not both. This reminds me of my psychology classes where they tried to describe behavioral tendencies using mathematic formulas, and when I asked the professor about solving such a formula I was basically told you couldn’t.

Update: Many, many thanks to Mike Neir for giving me an explanation that, while it doesn’t make me feel like an expert, has at least answered my initial “big picture” questions and has set me on the path to really understanding it. Thanks Mike, you rule.