IPv6 Static Routing

Route selection in IPv6 is identical to IPv4 — longest-prefix match first, then administrative distance — and the ipv6 route command is a near-mirror of ip route. The one genuinely new idea is the link-local next-hop, and it is exactly where the exam sets its trap.

ipv6 route <destination-prefix>/<length> { <next-hop> | <exit-interface> | <exit-interface> <next-hop> }

If link-local next-hops are awkward, why use them? Because they are stable: they do not change when you renumber the global prefix, which is a real event in IPv6. A static route pinned to a neighbour's link-local plus exit interface survives a renumber that would have broken a global-next-hop route — and OSPFv3 uses link-local next-hops for exactly this reason. For CCNA static routing the takeaway is narrower: if you choose link-local, you must add the exit interface.

Topology: R1 — R2. The transit link is 2001:DB8:0:12::/64 (R1 = ::1, R2 = ::2, and R2's link-local there is FE80::2). R2's LAN is 2001:DB8:0:2::/64. R1 must reach R2's LAN, then hold a default route toward the edge.

! Precondition — enable IPv6 forwarding (once, globally)
R1(config)# ipv6 unicast-routing

! Form 1 — global next-hop (recursive, most common)
R1(config)# ipv6 route 2001:DB8:0:2::/64 2001:DB8:0:12::2

! Form 3 — fully specified, REQUIRED for a link-local next-hop
! R1(config)# ipv6 route 2001:DB8:0:2::/64 GigabitEthernet0/0 FE80::2

! Default route (gateway of last resort)
R1(config)# ipv6 route ::/0 2001:DB8:0:12::2

R1# show ipv6 route static
IPv6 Routing Table - default - 5 entries
Codes: C - Connected, L - Local, S - Static, ...
S   ::/0 [1/0]
     via 2001:DB8:0:12::2
S   2001:DB8:0:2::/64 [1/0]
     via 2001:DB8:0:12::2

• S marks a static route; [1/0] is administrative distance 1 and metric 0 — the same defaults as an IPv4 static route.
• S ::/0 is the default route. ::/0 is to IPv6 exactly what 0.0.0.0/0 is to IPv4.
• Had you used the link-local form, the entry would read via FE80::2, GigabitEthernet0/0 — the exit interface is displayed because it is genuinely part of the route, and it is what makes the next-hop unambiguous.
• R2 still needs a route back toward R1's LAN, or a default toward R1. Otherwise the ping leaves cleanly and dies on the return — the same one-way failure you met in IPv4.

• Enable ipv6 unicast-routing first — without it the router addresses but does not forward IPv6.
• ipv6 route <prefix>/<len> takes a next-hop, an exit interface, or both — the same three forms as ip route.
• A global next-hop resolves recursively and can stand alone; a link-local next-hop must be fully specified with the exit interface.
• Default route = ipv6 route ::/0 <next-hop>, the direct analog of 0.0.0.0/0.
• Route selection is identical to IPv4 — longest-prefix match, then AD — and return routes are still required.
• Verify with show ipv6 route and show ipv6 route static; look for the S code and [AD/metric].