CompTIA Network+ (N10-009)Networking ConceptsHard
A network administrator is configuring an internal addressing scheme for a lab network that will never be routed on the public internet, similar in purpose to private IPv4 address ranges. Which IPv6 address type and prefix should be used?
- AGlobal unicast, 2000::/3
- BMulticast, ff00::/8
- CUnique local address, fc00::/7
- DLink-local, fe80::/10
Show answer & explanationAnswer & explanation
Correct answer: C. Unique local address, fc00::/7
Unique Local Addresses (ULA), defined by the fc00::/7 prefix, are the IPv6 equivalent of private IPv4 addressing (RFC 1918) and are intended for internal use, not routed on the public internet.
Why the other options are wrong
- A. Global unicast addresses (2000::/3) are publicly routable on the internet, the opposite of what's needed.
- B. Multicast addresses (ff00::/8) are used for one-to-many communication, not for general host addressing.
- D. Link-local addresses (fe80::/10) are confined to a single local segment and not routable even within a larger internal network.
IPv6 Unique Local Address (ULA)
ULA addresses use the fc00::/7 prefix and provide private, non-internet-routable addressing for internal IPv6 networks, similar to RFC 1918 private IPv4 space.
- Prefix range: fc00::/7 (commonly fd00::/8 in practice)
- Not routable on the public internet
- Analogous to IPv4 private addresses (10.x, 172.16.x, 192.168.x)
Memory trick: ULA = 'Unrouted Local Address' - stays home like private IPv4.