1.3 IPv6 Addressing Schemes, SLAAC & EUI-64

🎯 Key CompTIA Network+ Exam Takeaways

• IPv6 link-local addresses (fe80::/10) are mandatory and auto-generated on every interface for local segment communications.
• EUI-64 inserts FFFE into the middle of a 48-bit MAC address and inverts the 7th bit (Universal/Local bit).
• Stateless Address Autoconfiguration (SLAAC) uses ICMPv6 Router Solicitations and Router Advertisements to self-configure global addresses without DHCP.

IPv6 utilizes 128-bit hexadecimal addresses divided into eight 16-bit blocks separated by colons. Unlike IPv4, IPv6 eliminates broadcast addressing in favor of efficient Multicast (ff00::/8) and Anycast mechanisms.

Every IPv6-enabled interface automatically generates a link-local address in the fe80::/10 range. Link-local addresses facilitate neighbor discovery (NDP) and next-hop router adjacency on the local link, but routers never forward them across network boundaries.

Under EUI-64, an interface ID is created by inserting hex FFFE between the 24-bit OUI and the 24-bit vendor extension of a device's MAC address, followed by inverting the 7th bit to signify local administration.

⚠️ Common Pearson VUE Exam Traps

• Forgetting to flip the 7th bit when constructing an EUI-64 address from a MAC address.
• Confusing fe80::/10 (link-local, non-routable) with 2000::/3 (global unicast, public Internet).