A 64-bit interface ID is created by inserting the hex value of FFFE in the middle of the MAC address of the network card. You also learnt that network administrators will be able to use MAC addresses in order to create IPv6 addresses without the need of a DHCP server in your infrastructure.The second part of an IPv6 unicast or anycast address is typically a 64-bit interface identifier used to identify a host’s network interface. In this tutorial, you learnt how many bits there are in a MAC address which is 48 bits or 6 bytes. When we flip the seventh bit of this binary form, it becomes “00110100” which is “52” in decimal form.Īwesome, you finally got your final IPv6 in an EUI-64 format which is : 528A-BAFF-FEDE-15F3. In order to flip the seventh bit of the first byte of our MAC address, we need to convert “54” to a binary form. Now, you have to remember that you need to flip the seventh bit of the first byte. Your new IPv6 created address is now “54-8A-BA-FF-FE-DE-15-F3”. Now, we are going to add the reserved value “FFFE” to it, and add the last three bytes (which are specific to your own network card). In order to build an IPv6 address, first, you are going to isolate the first three bytes (which are reserved to the vendor) : “54-8A-BA”. When you are done, you flip the seventh bit of the first byte in order to make your EUI-64 globally unique.Īs a quick example, let’s take the “ 54-8A-BA-DE-15-F3″ which is a MAC address designed by Cisco Systems Inc. Well, the method is pretty simple : you take the first three bytes of the MAC address, add “FFFE” (which is a reserved value by the IEEE) and you add the last three bytes of your MAC address. So, how does one convert a MAC address to an IPv6 address?
As a quick reminder, an IPv6 address is made of six groups of 2 bytes, and it is also written in hexadecimal.Īs a consequence, there is a direct conversion from a MAC address to an IPv6 address, which is the basis of the EUI-64 format.ĭeveloped in RFC 2373, EUI-64 is a method that allows any host to have an IPv6 address, removing the need for a DHCP server that was heavily used in an IPv4 environment. This format is very similar to the IPv6 format. As we also saw, MAC addresses are made of hexadecimal numbers separated by hyphens or dots. Using MAC Addresses for IPv6Īs we discussed earlier, there are 48 bits in a MAC address. In practice, there are no such things as “ 64-bit” MAC addresses but network administrators often use this term in order to designate the “EUI-64” notation. IPv4, made of 32 bits, were extended to IPv6 which are made of 128 bits.
With the rise of IPv6, new specifications came in order to solve the scarcity of MAC addresses in the world.
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