Quiz Entry - updated: 2026.07.14
What IPv6 addresses does show ipv6 interface brief display per interface?
Two per interface: a link-local address (FE80::), valid only on the local link, and a globally routable global unicast address.
R1# show ipv6 interface brief
GigabitEthernet0/0/0 [up/up]
FE80::7279:B3FF:FE92:3130
2001:DB8:ACAD:1::1
Address types shown:
| Address | Purpose | Scope |
|---|---|---|
| FE80:: (Link-local) | Communication on the local link only | Single link/subnet |
| Global Unicast (e.g., 2001:...) | Globally routable address | Internet-wide |
Key facts:
- A link-local address is automatically generated when a global unicast address is assigned
- An IPv6 interface must have a link-local address, but does not require a global unicast address
show ipv6 interface [id](without "brief") also shows multicast group addresses (FF02::) the interface has joined
Tip: The link-local address (FE80::) is like a "conversation within the room" — it never leaves the local network segment. The global unicast is your "public phone number."
Go deeper:
IPv6 address (Wikipedia) — contrasts the link-local (FE80::/10) and global unicast scopes shown per interface.- Link-local address (Wikipedia) — why every IPv6 interface auto-generates an FE80:: address even without a global one.