April 2004
Intermediate to advanced
864 pages
20h 58m
English
Content preview from CCSP Self-Study: Securing Cisco IOS Networks (SECUR)Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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Network Address Translation and NAT Transversal
The IP version 4 (IPv4) addressing scheme of 32 bits, which is subdivided into classes based on the values of the first three high-order bits, must have seemed like overkill to the original pioneers of IP, because it theoretically supports over 4.2 billion unique addresses. Significant numbers of addresses are lost to the mechanics of IP, however, which renders two addresses for every subnet unusable (network and broadcast addresses). Additional addresses are lost to special classes, leaving only approximately 3.2 billion addresses available for use.
In the early days of the Internet, this was a significant number, but then the Internet started to become more and more popular, threatening to quickly ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.