IPv6 Static Route

An IPv6 static route is a manually configured route that tells the router how to reach an IPv6 remote network. Unlike dynamic routing protocols, static routes don't adjust automatically; they are fixed and must be maintained by the network administrator.

Just like in IPv4, the router needs a route to know where to forward packets. If no dynamic routing protocol is configured, a static route is required to communicate with remote networks.

To learn the concept of IPv6 static routes, let's look at an example together.

Figure 1 – Initial IPv6 Topology

• PC1 is in the 2001:DB8:1::/64 network.

• PC2 is in the 2001:DB8:2::/64 network.

• R1 and R2 are connected via 2001:DB8:10::/64.

PC1 wants to send traffic to PC2. R1 receives the packet but doesn't know how to reach the destination network, because the 2001:DB8:2::/64 network is not in its IPv6 Routing Table.

Figure 2 – Missing Static Route on R1

Without any static or dynamic route configured, R1 drops the packets and the communication between PC1 and PC2 fails.

To fix the issue, as a network administrator, we can configure an IPv6 static route on R1, pointing to R2's IPv6 address 2001:DB8:10::2.

Figure 3 – Adding an IPv6 Static Route on R1

At this point, R1 is now able to forward traffic destined to 2001:db8:2::/64 to its next hop 2001:db8:10::2.
However, R2 still doesn't know how to reach the 2001:DB8:1::/64 network.

To complete the communication, we must add a return IPv6 static route on R2, pointing to R1.

Figure 4 – IPv6 Static Route on R2

With static routes now configured on both routers, communication is possible between PC1 and PC2.

Figure 5 – IPv6 Static Route on R1 Working

Traffic from PC1 reaches PC2 by using R1 and R2.

Figure 6 – IPv6 Static Route on R2 for Return Path

Reply packets from PC2 are returned to PC1 using the static route on R2 pointing to R1.

Enough theory. Let's move into the Cisco IOS CLI to show you every step to configure an IPv6 Static Route.

Figure 7 – Lab Topology IPv6 Static Route

Step 1 – Enable IPv6 Routing

First, you need to know that Cisco routers do not have IPv6 routing enabled by default.
We must activate this feature on both routers R1 and R2 using the command ipv6 unicast-routing.

R1# conf t
Enter configuration commands, one per line.  End with CNTL/Z.
R1(config)# ipv6 unicast-routing

If this command is not configured, the router will still accept and assign IPv6 addresses to its interfaces. Local communication may work, but the router will not forward IPv6 packets between interfaces, and routing will not occur.

Step 2 – Configure IPv6 Addresses

Now let's assign IPv6 addresses to the router interfaces based on the topology.

R1(config)# interface g0/0
R1(config-if)# ipv6 address 2001:DB8:10::1/64
R1(config-if)# no shutdown
%LINK-5-CHANGED: Interface GigabitEthernet0/0, changed state to up
%LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/0, changed state to up
R1(config-if)# exit

R1(config)# interface g0/1
R1(config-if)# ipv6 address 2001:DB8:1::10/64
R1(config-if)# no shutdown
%LINK-5-CHANGED: Interface GigabitEthernet0/1, changed state to up
%LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/1, changed state to up
R1(config-if)# end

After configuring the interfaces, the router will automatically learn:

• A connected route for each subnet (C)

• A local route for each interface IP (L)

You can check the IPv6 Routing Table by using show ipv6 route.

R1# show ipv6 route
IPv6 Routing Table - 5 entries
Codes: C - Connected, L - Local, S - Static, R - RIP, B - BGP
       U - Per-user Static route, M - MIPv6
       I1 - ISIS L1, I2 - ISIS L2, IA - ISIS interarea, IS - ISIS summary
       ND - ND Default, NDp - ND Prefix, DCE - Destination, NDr - Redirect
       O - OSPF intra, OI - OSPF inter, OE1 - OSPF ext 1, OE2 - OSPF ext 2
       ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2
       D - EIGRP, EX - EIGRP external
C   2001:DB8:1::/64 [0/0]
     via GigabitEthernet0/1, directly connected
L   2001:DB8:1::10/128 [0/0]
     via GigabitEthernet0/1, receive
C   2001:DB8:10::/64 [0/0]
     via GigabitEthernet0/0, directly connected
L   2001:DB8:10::1/128 [0/0]
     via GigabitEthernet0/0, receive
L   FF00::/8 [0/0]
     via Null0, receive

Step 3 – Add IPv6 Static Route on R1

Now let's configure the static route on R1 to reach the 2001:DB8:2::/64 network behind R2.

R1# conf t
Enter configuration commands, one per line.  End with CNTL/Z.

We specify the destination prefix:

R1(config)# ipv6 route ?
  X:X:X:X::X/<0-128>  IPv6 prefix
R1(config)# ipv6 route 2001:db8:2::/64 ?
  Dialer           Dialer interface
  Ethernet         IEEE 802.3
  FastEthernet     FastEthernet IEEE 802.3
  GigabitEthernet  GigabitEthernet IEEE 802.3z
  Loopback         Loopback interface
  Serial           Serial
  Vlan             Catalyst Vlans
  X:X:X:X::X       IPv6 address of next-hop

We then define the next-hop IPv6 address of R2:

R1(config)# ipv6 route 2001:db8:2::/64 2001:db8:10::2
R1(config)# exit

The command ipv6 route 2001:db8:2::/64 2001:db8:10::2 means:
To reach the 2001:DB8:2::/64 network, forward packets to R2's IPv6 address 2001:db8:10::2 on the shared link.

We can now verify the IPv6 Routing Table:

R1# show ipv6 route
IPv6 Routing Table - 6 entries
Codes: C - Connected, L - Local, S - Static, R - RIP, B - BGP
       U - Per-user Static route, M - MIPv6
       I1 - ISIS L1, I2 - ISIS L2, IA - ISIS interarea, IS - ISIS summary
       ND - ND Default, NDp - ND Prefix, DCE - Destination, NDr - Redirect
       O - OSPF intra, OI - OSPF inter, OE1 - OSPF ext 1, OE2 - OSPF ext 2
       ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2
       D - EIGRP, EX - EIGRP external
C   2001:DB8:1::/64 [0/0]
     via GigabitEthernet0/1, directly connected
L   2001:DB8:1::10/128 [0/0]
     via GigabitEthernet0/1, receive
S   2001:DB8:2::/64 [1/0]
     via 2001:DB8:10::2
C   2001:DB8:10::/64 [0/0]
     via GigabitEthernet0/0, directly connected
L   2001:DB8:10::1/128 [0/0]
     via GigabitEthernet0/0, receive
L   FF00::/8 [0/0]
     via Null0, receive

The route to 2001:DB8:2::/64 is now visible and marked with an S for static.

Reverse Configuration on R2

First, enable IPv6 routing on R2:

R2# conf t
Enter configuration commands, one per line.  End with CNTL/Z.
R2(config)# ipv6 unicast-routing

Now configure the IPv6 addresses on R2 interfaces.

R2(config)# interface g0/0
R2(config-if)# ipv6 address 2001:DB8:10::2/64
R2(config-if)# no shutdown
%LINK-5-CHANGED: Interface GigabitEthernet0/0, changed state to up
%LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/0, changed state to up
R2(config-if)# exit

R2(config)# interface g0/2
R2(config-if)# ipv6 address 2001:DB8:2::10/64
R2(config-if)# no shutdown
%LINK-5-CHANGED: Interface GigabitEthernet0/2, changed state to up
%LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/2, changed state to up
R2(config-if)# exit

R2 also needs a static route to reach the 2001:DB8:1::/64 network behind R1.

R2(config)# ipv6 route 2001:DB8:1::/64 2001:DB8:10::1
R2(config)# end

Now verify the IPv6 Routing Table on R2:

R2# show ipv6 route
IPv6 Routing Table - 6 entries
Codes: C - Connected, L - Local, S - Static, R - RIP, B - BGP
       U - Per-user Static route, M - MIPv6
       I1 - ISIS L1, I2 - ISIS L2, IA - ISIS interarea, IS - ISIS summary
       ND - ND Default, NDp - ND Prefix, DCE - Destination, NDr - Redirect
       O - OSPF intra, OI - OSPF inter, OE1 - OSPF ext 1, OE2 - OSPF ext 2
       ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2
       D - EIGRP, EX - EIGRP external
S   2001:DB8:1::/64 [1/0]
     via 2001:DB8:10::1
C   2001:DB8:2::/64 [0/0]
     via GigabitEthernet0/2, directly connected
L   2001:DB8:2::10/128 [0/0]
     via GigabitEthernet0/2, receive
C   2001:DB8:10::/64 [0/0]
     via GigabitEthernet0/0, directly connected
L   2001:DB8:10::2/128 [0/0]
     via GigabitEthernet0/0, receive
L   FF00::/8 [0/0]
     via Null0, receive

At this point, both routers can reach each other's networks using static routes.

Step 4 – Verify End-to-End IPv6 Connectivity

Now let's test the connectivity between PC1 and PC2 using IPv6, from PC1 (Windows CLI):

PC1> ping -6 2001:DB8:2::1
Pinging 2001:DB8:2::1 with 32 bytes of data:
Reply from 2001:DB8:2::1: time=2ms
Reply from 2001:DB8:2::1: time=2ms
Reply from 2001:DB8:2::1: time=3ms
Reply from 2001:DB8:2::1: time=2ms

Ping statistics for 2001:DB8:2::1:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),

The -6 flag tells the Windows ping command to explicitly send the request as IPv6.
Since PC1 supports both IPv4 and IPv6, this flag removes any ambiguity when the destination is specified as an IPv6 address.

IPv6 connectivity is now fully operational between both endpoints.

• An IPv6 static route is a manually defined route used to reach a remote IPv6 network.

• It's essential when no dynamic routing protocol (like OSPFv3) is in use.

• Static routes must be configured and updated manually by the network administrator.

Key Commands

Enable IPv6 routing:

R1# conf t
Enter configuration commands, one per line.  End with CNTL/Z.
R1(config)# ipv6 unicast-routing

Configure a static route with next-hop:

R1(config)# ipv6 route 2001:db8:2::/64 2001:db8:10::2

• Static routes are marked with S in the routing table.

• They have an Administrative Distance of 1 by default.

While it's possible to configure routes using the outgoing interface, the CCNA exam focuses on the next-hop IPv6 address method.