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Showing posts with label IPv4. Show all posts
Showing posts with label IPv4. Show all posts

An Introduction to IPv6

Written By Unknown on Monday, 6 June 2011 | 00:38

Right now, most of the world is using IPv4
(Internet Protocol version 4). The problem is that it does not allow for enough addresses. The world is just too big of a place. Enter IPv6. It provides vastly more addresses (2^128) and is the future of the web. Most users will not notice a difference, but networking personnel will (you can test your IPv6 connectivity here)

An IPv6 address has a few differences from IPv4. The first is that it is in hexadecimal instead of decimal. The second is that it is split up into larger segments and more of them. The third is that it uses colons (:) rather than periods (.) to divide these segments. In the end, one does not resemble the other. This is good because it prevents confusing the two.


Hexadecimal is better than decimal for a few reasons. For one, it takes up less space. The number “255″ is “FF” in hex; that is %50 smaller. Hexadecimal also relates more closely to binary. The number “1111″ is “15″ in decimal but “F” in hex. So “11111111″ is “FF” in hex, which is a much cleaner conversion than “255″ is. The downside is that humans typically think in decimal, so working with hex takes some getting used to.

IPv6 has a much larger address size. It has eight sections to it. IPv4 had half of that. The sections themselves are larger too: each one has four digits. IPv4 could only have three, and that only went to 255 tops. It should be obvious why this new address can afford all the room we have come to need. Hopeful it will for a long time. Here is a sample address.

FF00:00FF:0000:0000:0000:02f3:0000:0001

At this point, you may begin to see the down side to IPv6: it is long and hard to remember. To make them more human readable, there are a few conventions to short address when you have a lot of zeros present. First of all, you can skip leading zeros, so “0001″ becomes “1″ and “02f3″ becomes “2f3″ (IPv4 did this too). Second, groups of all zeros can be abbreviated to “::” (a double colon) once; you put nothing there. That makes “:0000:0000:0000:” reduce to “::” but “:0000:” cannot as it would be ambiguous. You can apply the first rule, making it “:0:” now. Putting all these rules into place gives us the following address.

FF00:FF::2f3:0:1

This address is about as long as an IPv4 number. Notice how the “00FF” shrank to “FF” and the “FF00″ did not. That was done intentionally to show the difference between leading and trailing zeros.

There is one more thing you really need to know if you are working with IPv6. The loop-back address, which was 127.0.0.1 in IPv4, is ::1 now. It works exactly the same way. You will have to use the ping6 command in Windows or Linux, so ping6 ::1 is what you would type into the command line. This will give many XP users an error as IPv6 may not be enabled on your computer. We have guides on how to enable IPv6 in XP, and how to assign IPv6 addresses in Linux.

Some other factoids about IPv6 are that it has is easier to route, more secure, and works better with mobile technology. There are changes to the way the packets of information are sent that makes it more efficient (e.g. better headers). It is more secure because it requires the use of IPSec, which is only optional in IPv4. IPv6 has an address recovery system, so when you change locations, it tries to keep the same address. These are are some of the that US government is switching over to it.

I should note that IPv6 has been found to have vulnerabilities. Malware tunneling is described in an article (note: a .pdf file) from the us-cert.gov site. It often has to do with how firewalls are configured. Different sources may give different opinions on how secure IPv6 is.

Wondering what happend to IPv5? It did exist. It was developed in the 1970′s to be used in audio and video streaming. It was called the Internet
Stream Protocol. It did not get far past the experimental stage and was never adopted. Ideas from it helped to form IPv6.

Test Your IPv6 Connectivity

Written By Unknown on Friday, 14 January 2011 | 11:04

You may have seen an increasing number of articles about IPv6 in the past year. IPv6 is an Internet Protocol that has been designed as the successor of the currently used IPv4 protocol. IPv4 has been in use since the 80s and it is quickly coming to its limits. The main problem with it is that IPv4 runs out of available IP address space as its limit is around 4 billion IP addresses which servers, ISPs, Internet users, devices and websites have to share.

IPv6 offers a larger address space. The move from IPv4 to IPv6 is difficulty as it requires a coordinated effort from all parties including Internet users. Users with improperly configured computers may experience slowdowns, timeouts or other connectivity issues when the Internet moves to the IPv6 protocol.

Will you have troubles? You can find out if you run the IPv6 test. The test is an Open Source script that runs using JavaScript. Just visit the website http://test-ipv6.com and wait until the test has finished. The IPv6 test runs a series of tests including the browser’s IPv4 and IPv6 capabilities, IPv4 and IPv6 connectivity with and without DNS records and a test that checks if the ISP’s DNS server uses IPv6.


A click on test data reveals details about the tests.


Another click on Technical Info leads to a page that offers technical information about each test which may provide clues to troubleshoot the issue.

The most important test at this point in time for the majority of users is the dual stack test. There will be a transition period where websites and services can be reached via IPv4 or IPv6. The user’s computer now needs to pick one of the protocols and use it for the connection which means that devices that only support IPv4 at this time can still connect to the websites. Connectivity issues occur if this is broken.

Major services and websites will switch to IPv6 for a 24 hour period on World IPv6 day on June 8. Among them Google, Facebook and Yahoo. That’s where the dual stack DNS record support can be tested in a life environment.
 
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