A network technician is configuring an IPv6 static route on a Cisco router. The destination network is 2001:DB8:ABCD::/48, and the next-hop IPv6 address is FE80::2 on the GigabitEthernet0/1 interface. Which command correctly configures this static route?
- Aipv6 route 2001:DB8:ABCD::/48 next-hop FE80::2
- Bipv6 route 2001:DB8:ABCD::/48 GigabitEthernet0/1 FE80::2
- Cipv6 route 2001:DB8:ABCD::/48 FE80::2
- Dipv6 route 2001:DB8:ABCD::/48 GigabitEthernet0/1
Show answer & explanationAnswer & explanation
Correct answer: B. ipv6 route 2001:DB8:ABCD::/48 GigabitEthernet0/1 FE80::2
When using a link-local address (FE80::/10) as a next-hop for an IPv6 static route, it is mandatory to also specify the outgoing interface. This is because link-local addresses are only unique on a local link, and the router needs to know which specific interface to use to reach that next-hop. Option C correctly includes both the outgoing interface and the link-local next-hop address.
Why the other options are wrong
- A. The `next-hop` keyword is not part of the standard `ipv6 route` command syntax for specifying the next-hop.
- C. This command is incomplete. When the next-hop is a link-local address, the outgoing interface must also be specified.
- D. This command specifies only the outgoing interface, but not the specific link-local next-hop address, which is required when the next-hop is a router on that segment.
IPv6 Static Route with Link-Local Next-Hop
When configuring an IPv6 static route with a link-local address (FE80::/10) as the next-hop, it is mandatory to specify the outgoing interface because link-local addresses are only significant on the local link.
- Link-local addresses are not globally routable.
- Requires `ipv6 route <destination> <interface> <link-local-next-hop>` syntax.
- Ensures the router knows which specific local link to use for the next-hop.
Memory trick: For a link-local IPv6 hop, you need both the road (interface) and the house number (next-hop).