August 2011
Intermediate to advanced
180 pages
5h 53m
English
Content preview from Packet Guide to Routing and SwitchingBecome 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,
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.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.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.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.
Chapter 7. Network Address Translation
The world has run out of IPv4 address space. Of course, this is not really news. In 2011 it was announced that some of the last five /8s of publicly available IPv4 address space were being allocated.
Since then, IPv4 address space depletion has been a continuing concern. Trends such as the Internet of Things (IoT) promise to add IP addresses to everything from cars to refrigerators. The simple truth is that there are not enough addresses to go around (and this has been the case for several years).
Many believe that IPv6, with its vast 128-bit addressing, will save the Internet. To date there have been a series of IPv6 days in which organizations are challenged and encouraged to transition from IPv4 to IPv6. Given these factors, the world should be running on IPv6. But it is not. One of the biggest reasons for this is network address translation (NAT).
NAT is described in RFC 1631as a technique by which a single IPv4 public address can be used by several computers. This is because the computers actually use private addresses (also known as RFC 1918 addresses) which are translated into the public address. The effect is that the number of IPv4 public addresses needed is smaller than the number of computers. It works so well that in all likelihood, we will continue to rely on NAT.
NAT describes the process of converting traffic coming from private, inside IPv4 addresses to traffic that appears to have come from a globally unique outside address. The ...
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,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
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.