IP and Subnets for Dummies
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A better starting point, IMHO, is the CompTIA Network+. It covers all of this well and is cheap. No need to take the exam, the Exam Cram book is allthat you need.
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You could also check out the CCNA courses over on Cybrary (http://cybrary.it). I've got an account there and have been checking them out when I have time.
You are definitely right about it being time consuming!
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Here's a quick breakdown: http://serverfault.com/questions/12854/cidr-for-dummies. I was going to try to explain most of that, but they're hitting the high points.
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@scottalanmiller said:
A better starting point, IMHO, is the CompTIA Network+. It covers all of this well and is cheap. No need to take the exam, the Exam Cram book is allthat you need.
which book would you recommend?
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@Kelly said:
Here's a quick breakdown: http://serverfault.com/questions/12854/cidr-for-dummies. I was going to try to explain most of that, but they're hitting the high points.
thanks i'll look at this URL in more detail tomorrow
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That is the one certification I have, @scottalanmiller, the CompTia Net+. We coverdd binary and converting back and forth
However, I can't say I spend a whole lot of time using it today.. but it still applies.
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@Joel said:
@scottalanmiller said:
A better starting point, IMHO, is the CompTIA Network+. It covers all of this well and is cheap. No need to take the exam, the Exam Cram book is allthat you need.
which book would you recommend?
I used the Exam Cram back in the day, it was very good.
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I finished the Network+ at the end of last September and the Security+ at the end of last December. Here are the resources I used for studying the Network+ material:
- Lynda.com Network+ by Mike Myers N10-006 ( http://www.lynda.com/search?q=network%2B+mike+myers )
- Professor Messer training videos ( http://www.professormesser.com/network-plus/n10-006/n10-006-course-index/ )
- Techwise TV | Networking 101 ( https://www.youtube.com/playlist?list=PL2D6D953CAEEA70A6 )
- Cybrary.IT ( https://www.cybrary.it/course/comptia-network-plus/) *I had to stop watching these because the guy presenting has some weird problem where he can't stop moving his hands whenever he talks, and it is HORRIBLY distracting.
- Exam Cram N10-006 ( http://www.amazon.com/CompTIA-Network-N10-006-Exam-Cram/dp/078975410X/ref=sr_1_1?ie=UTF8&qid=1453765942&sr=8-1&keywords=n10-006+exam+cram )
- ExamCompass for practice tests ( http://www.examcompass.com/comptia/network-plus-certification/free-network-plus-practice-tests )
I would suggest checking with your local library to see if they offer free access to Lynda.com. There is a lot of great content available for Network Basics, including Network+ and CCNA specific content. I'm not sure I would have shelled out the cash for access if I didn't already have it available to me through my school. Professor Messer and Exam Cram will probably be more than enough to help with the basics.
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I use this all the time
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Everyone's pretty much covered that your IP ranges won't really have any effect for security or anything. But I guess to try to answer a little more of what you're asking, I'd say subnetting is really for situations where you'd walk in to set up a network given guidelines like "We need 20 subnets, with up to 600 addresses on each subnet", or "We need 5 subnets, with however many addresses on each".
Subnetting's pretty much just the math that lets you take those guidelines and make sure you'll have them covered. Like others mentioned, it's based on binary.
For example, it ends up on a basic level not really mattering whether you need 600 addresses or 700 per subnet, because everything is based on the pattern 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024...
Once you need more than 512 addresses per subnet (actually 510 for other reasons), your subnetting results won't change up until the point where you'd need over 1024 (really 1022).
Solving to make sure you have the number of subnets you need is also based on using that same number pattern to split up the addresses you have to work with.
Other sites can explain binary counting a lot better than I could try to, but 8 bits of data can work together to represent values from 0 through 255 like we see in those network addresses (256 values total since we started at 0).
Any address like 10.2.208.144 doesn't tell us much by itself about what's going on around it, but if you know what the mask is from /8 to /31 or so, it'll be enough to figure out the usable range of how many other addresses might be in its network, what the subnet's broadcast address is, where the next subnet starts, and how many other subnets you have to work with.
I watched Jeremy Cioara's CBT Nuggets and thought he was great. He talked about how much trouble people can have with subnetting and its math, but to me he taught it really clearly. He joked being facetious once about starting to use 10.x.x.x ranges instead of 192 ranges because they're cooler and "more professional", but really there's not any hidden benefit before your guidelines require you to have more of a plan for your subnets, for reasons others have mentioned.
In the past, the range of addresses was split up into different ranges or classes, but they don't really come into play any more. About right after I learned about the classes, I learned they come up more on certification tests than in other environments.
