Jared Heinrichs

  • Technology Blog
  • Winnipeg Computer Repair
  • Winnipeg Photographer
  • Cooking With Jared
You are here: Home / Uncategorized / Microsoft IPv6 address vs IPv6 EUI-64 adress plus what is that % mean?

May 20, 2014 By Jared Heinrichs Leave a Comment

Microsoft IPv6 address vs IPv6 EUI-64 adress plus what is that % mean?

Working through my cisco certification you learn about EUI-64. Essentially it takes your make address and converts it into an IPv6 address. Let’s look at an example:

  • MAC: 0000.1111.1111.1111
  • IPv6 EUI-64 Link Local Address – FE80::0200:111FF:FE1:1111

Let’s look at a couple of things first. You might notice a “0” turned into a “2” and “FFFE” was thrown in the middle.

The “7th” bit always get’s inverted when making a EUI-64 address. Let’s look at the bits and see how “2” was made. Below is the binary representation of the first 16 bits of Local Identifier.

In hex each character has a potential value from 0->15. That means Each character can be represented in binary by 4 bits. Let’s break down “0000” into 4 separate sections. I will make the 7th bit red and underlined.

0000 0000 0000 0000

Let’s “flip” the bit. To flip the bit “0” becomes a “1” and a “1” becomes a “0”.

0000 0010 0000 0000

the character equals “0010” in binary which is equal to:

(8×0)+(4×0)+(2×1)+(1X0) = 2

Because of this the conversion then looks like “0200”

Next because we need a host ID that is 64bits they take the 48bit Mac address and add 16 more bits and “pad the middle” of the address with “FFFE”.

You might be wondering why I am mentioning all this! Microsoft saw early on that people and computers could be easily tracked by companies if their addresses were made up of their never changing “Burned-in” Mac addresses!

Because of this RFC 3041 was made. It was made to create a random generated Host-ID so that companies like Google couldn’t easily track you.

Click the picture to see it blown up. Notice how the MAC address isn’t inside the Link-Local IPv6 Address!

windows-ipconfig-output

Here’s a link from Microsoft. The randomly generated info is near the bottom: http://msdn.microsoft.com/en-us/library/aa915616.aspx

Notes on EUI-64:

http://howdoesinternetwork.com/2013/slaac-ipv6-stateless-address-autoconfiguration

So what is up with the % and then number in Microsoft’s IPv6 addresses. In IP 4 what would happen if you had an IP address on separate NIC’s that were in the same network?

eg: NIC #1 – 10.1.1.1 /24 and NIC #2 set to 10.1.1.2 /24?

Wouldn’t work right?

Well the % serves as a zone identifier! http://superuser.com/questions/99746/why-is-there-a-percent-sign-in-the-ipv6-address

Filed Under: Uncategorized

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Categories

  • Board Game Rules
  • Camera
  • Computer Hardware
    • Blackberry
    • drivers
    • iPad
    • Magic Jack
    • USB
  • Damn Small Linux
  • Exam Notes
  • Facebook
  • FREE Flashcards
  • Games
    • PC
      • League of Legends
    • Wii
    • xbox 360
  • Music
  • Networking
    • Cisco Certification
    • Mitel
    • Palo Alto Firewall
  • News
    • Google
    • Microsoft
  • Operating System
    • Active Directory (2003)
    • Android
    • Command Prompt
    • Damn Small Linux
    • Group Policy
    • Hyper-V
    • IIS
    • ISA 2006
    • Mac OS X
    • Microsoft Exchange Server
    • Powershell
    • Security
    • SME Server
    • Terminal Server 2003
    • Ubuntu Linux
      • Adito Web SSL VPN
      • OpenVpn-als
      • Webmin
    • Virtual Machine Manager
    • Windows 2003 SBS
    • Windows 2003 Server
    • Windows 2008
    • Windows 2008 R2
    • Windows 2012R2
    • Windows 7
    • Windows 8
    • Windows Command Line
    • Windows Deployment Services
    • Windows Server Backup
    • Windows Vista
    • Windows XP
  • Phones
  • Photography
  • Photos
    • Animals
    • Misc
    • Nature
    • Portraits
  • Portfolio
  • Programming
    • CSS
    • HTML
    • jQuery
    • MySQL
    • PHP
    • Script
  • Programs
    • Acrobat
    • Acrobat Reader
    • Adobe Dreamweaver
    • Adobe Illustrator
    • Adobe Photoshop
    • Anti-virus Software
    • Antivirus
    • Backup Exec
    • Bittorent
    • Blackberry BESADMIN
    • Internet Explorer 9
    • Lightroom
    • Microsoft Office
    • Netbeans
    • Onenote
    • Outlook
    • Shelby
    • Sysprep
    • Trend
    • Video Editing
    • Visual Studio
    • Windows Live Writer
    • WireShark
    • XP Mode
    • Zarafa
  • Recipe
  • Review
  • Software Links
  • Troubleshooting
  • Uncategorized
  • Videos
  • Web Applications
    • Brage
    • Google
    • Spiceworks
    • Wordpress
  • Web Browsers
    • Internet Explorer
  • Web Server
    • XAMPP
  • Winnipeg
    • ISP

Try searching this site!

Copyright © 2021 Winnipeg Web Design