CCNP Route Lab 8-3, Configuring 6to4 Tunnels

CCNP Route Lab 8-3, Configuring 6to4 Tunnels

Topology

ccnp-route-lab-configuring-6to4-tunnels

Objectives

  • Configure EIGRP for IPv4.
  • Create a 6to4 tunnel.
  • Configure static IPv6 routes.

Background
In this lab, you configure EIGRP for full connectivity between all IPv4 subnets. You then create a 6to4 tunnel and create static routes over it.

Note: This lab uses Cisco 1841 routers with Cisco IOS Release 12.4(24)T1 and the Advanced IP Services image c1841 -advipservicesk9-mz.124-24.T1 .bin. You can use other routers (such as a 2801 or 2811) and Cisco IOS Software versions if they have comparable capabilities and features. Depending on the router model and Cisco IOS Software version, the commands available and output produced might vary from what is shown in this lab.

Required Resources

  • 3 routers (Cisco 1841 with Cisco IOS Release 12.4(24)T1 Advanced IP Services or comparable)
  • Serial and console cables

Step 1: Prepare the routers for the lab.
Clear previous configurations by erasing the startup configuration and reloading the routers. After the routers are reloaded, set up the appropriate hostnames.

Step 2: Configure loopbacks and physical interfaces.
a. Configure the loopback interfaces with IPv4 addresses and IPv6 addresses, where appropriate. Also configure the serial interfaces with the IPv4 addresses shown in the diagram. Set the clock rates on the appropriate interfaces and the bandwidth on all serial connections.

b. Verify that you have local subnet connectivity with ping.

Step 3: Configure EIGRP.
Configure EIGRP for AS 1 for the major networks 172.16.0.0 and 10.0.0.0 on all three routers. You should have full IPv4 connectivity.

Step 4: Configure a manual IPv6 6to4 tunnel.
A tunnel is a logical interface that acts as a logical connection between two endpoints. It is similar to a loopback interface in that there is no corresponding physical interface, but it is different in that there is more than one router involved. A 6to4 tunnel uses special IPv6 addresses in the 2002::/16 address space. The first 16 bits are the hexadecimal number 2002, and the next 32 bits are the original source IPv4 address in hexadecimal form. The remaining bits can be specified as shown in Step 4c. A 6to4 tunnel does not require a destination address because it is not a point-to-point link.

In this step, you configure additional 6to4 IPv6 loopback interfaces to represent LANs on R1 and R3, and then configure a 6to4 tunnel to provide IPv6 connectivity between the loopback interfaces.

a. Add the following loopbacks to R1 and R3.

b. Configure a 6to4 tunnel using the interface tunnel number command to get to the tunnel interface configuration prompt. For simplicity, use interface number 0.

c. Set the tunnel mode with the tunnel mode ipv6ip 6to4 command. Then set up the IPv6 address with the ipv6 address address/mask command. The R1 address is 2002:AC10:0C01:1::1/64, because AC10:0C01 corresponds to 172.16.12.1, with 172 being AC, 16 being 10, 12 being C, and 1 being 1. The 1 after this address is just a more specific subnet, and the 1 at the end is the host address. The R3 address is 2002:AC10:1703:1::3/64. The two addresses are not in the same /64 subnet. After setting the IPv6 addresses, set the source interface for the tunnel with the tunnel source type/number command.

d. Now that all the tunnel settings are set, enable IPv6 routing with the ipv6 unicast-routing command, and set up an IPv6 static route for the whole 2002::/16 network with the global command ipv6 route address/mask interface, with the interface being the tunnel you just created.

e. Enter the following commands on R3.

f. Verify that you can ping the other side of the tunnel from R1 to R3, and ping the newly created loopback interfaces from each router .

Step 5: Configure static IPv6 routes.
Just like IPv4, IPv6 can have static routes entered into its routing table. You already created one for the 2002::/16 network in Step 4. Now you will configure a static route on R1 telling it how to get to the R3 loopback 0 address. On R3, you will configure a static route pointing to R1.

a. Static routes with a next-hop IPv6 address are created with the ipv6 route address/mask next-hop command. The next hop for both routers is the IPv6 address of the other end of the tunnel.

b. Verify the IPv6 static routes using the show ipv6 route command or by pinging the remote loopback address from each router.

c. From R1 and R3, ping the loopback 0 IPv6 address of the opposite router.

d. Use the following Tcl script on R1 and R3 to verify network connectivity.

Were all pings successful?
All pings should be successful for R1 and R3.

e. Run the Tcl script on R2. Were all IP addresses reachable? Explain.
No. R2 cannot reach the R1 and R3 IPv6 loopback interface addresses or the IPv6 addresses for the tunnel. R2 simply provides a physical path for the tunnel and has no knowledge of it or the R1 and R3 IPv6 loopback addresses.

Router Interface Summary Table

Router Interface Summary
Router Model Ethernet Interface
#1
Ethernet Interface
#2
Serial Interface
#1
Serial Interface
#2
1700 Fast Ethernet 0
(Fa0)
Fast Ethernet 1
(Fa1)
Serial 0 (S0) Serial 0/0/1
(S0/0/1)
1800 Fast Ethernet 0/0
(Fa0/0)
Fast Ethernet 0/1
(Fa0/1)
Serial 0/0/0
(S0/0/0)
Serial 0/0/1
(S0/0/1)
2600 Fast Ethernet 0/0
(Fa0/0)
Fast Ethernet 0/1
(Fa0/1)
Serial 0/0 (S0/0) Serial 0/1 (S0/1)
2800 Fast Ethernet 0/0
(Fa0/0)
Fast Ethernet 0/1
(Fa0/1)
Serial 0/0/0
(S0/0/0)
Serial 0/0/1
(S0/0/1)
Note: To find out how the router is configured, look at the interfaces to identify the type of router and how many interfaces the router has. Rather than list all combinations of configurations for each router class, this table includes identifiers for the possible combinations of Ethernet and serial interfaces in the device. The table does not include any other type of interface, even though a specific router might contain one. For example, for an ISDN BRI interface, the string in parenthesis is the legal abbreviation that can be used in Cisco IOS commands to represent the interface.

Device Configurations (Instructor version)

Router R1

Router R2

Router R3

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