The following table shows five prefixes and MAC unabbreviated IPv6 addresses convert these to the shortest possible abbreviated IPv6 address. In other words, use the solicited node multicast prefix with those last 6 hex digits of the unicast IPv6 address. throw ff:fe in the middle: 52:74:f2:ff:fe:b1:a8:7f reformat to IPv6 notation 5274:f2ff:feb1:a87f. take the mac address: for example 52:74:f2:b1:a8:7f. The conversion procedure is as given below. This link-local IPv6 is infered from the NIC’s mac address. This multicast address is formed by taking the unicast address, and replacing the first 104 bits (26 hex digits) with FF02::1:FF00:0/104. I need to convert a Mac Address into an IPv6 Link Local address. Do some math on the first byte of the MAC address to invert (flip) the 7 th of 8 bits (counting left-to-right)įor this exercise, take the listed prefixes and MAC addresses, and create the IPv6 address the device would use.Įxtra credit: Also, if interested, you can think about the solicited node multicast address the host would use along with the unicast address.Insert hex FFFE in the middle between the two, completing the 16 hex digits in the 2nd half of the number.Split the MAC into two halves, each 6 hex digits / 3 bytes / 24 bits long.EUI-64 rules used by SLAAC tell you how to make the last 64 bits, as follows: However, then you have to convert the first byte, or at least the 2 nd hex digit, to binary and back. First, you use the learned prefix as the first 64 bits. Using these two facts, the process to form the full 128-bit IPv6 unicast address is pretty simple. A 64-bit IPv6 prefix (typically learned from a router).The EUI-64 process to derive an IPv6 address begins with two facts, followed by a process that uses those facts. One of the ways I learn a new scripting language is to implement a subroutine to convert a network MAC addr into the IPv6 link-local address, as described in RFC 4862.
Related links: Deeper info from the ICND2 OCG book Today’s post lists sample problems the follow-up post will show the answers.
The goal: Starting with a MAC address and a /64 IPv6 prefix, predict the IPv6 address the host would use if using IPv6 Stateless Auto Address Configuration (SLAAC). It’s icky for two reasons: it requires you to think in binary, and it rhymes. This post starts a new type of review post for #ICND2 or #CCNA: the icky EUI-64 drill.