1 IPv6 Exercises

APNIC Training IPv6 Tutorial Exercises Students Manual April 9-11, 2007 Dhaka, Bangladesh

2 IPv6 Exercises

Contents Exercise 1 : IPv6 Host Configuration Exercise 2 : IPv6 Subnetting Exercise 3 : IOS Introduction Exercise 4 : IPv6 IX Topology Exercise 5 : IPv6 Tunnelling Topology

3 IPv6 Exercises

Exercise 1 IPv6 Host Configuration In the following exercise you will configure IPv6 as the default configuration on your pc. You will be able to verify your configuration by pinging other IPv6 enabled machines in a peer to peer IPv6 network About IPv6 Autoconfiguration In IPv4 dynamic address configuration is achieved through the use of DHCP (Dynamic Host Configuration Protocol) which allows the host machine to obtain an IPv4 address as well as other information required for network connectivity and operation (eg default routers, WINS Server for Windows and the DNS ( Domain Name System) server address. IPv6 supports a similar protocol called DHCPv6. There are though still issues in this implementation and it is therefore not currently widely used. However, because IPv6 also has a stateless autoconfiguration protocol (RFC2462) that doesn’t require or rely on any DHCP server, IPv6 addresses can still be automatically assigned. There is no need for any manual configuration on the host machine and only limited configuration required for the routers..

4 IPv6 Exercises

Configuring IPv6 under Windows XP Source: http://www.microsoft.com/technet/itsolutions/network/ipv6/ipv6faq.mspx To install the IPv6 protocol for Windows XP with SP2, do the following:

1. Log on to the computer with a user account that has privileges to change the network configuration.

2. Click Start, click Control Panel, and then double-click Network

Connections.

3. Right-click any local area connection, and then click Properties.

4. Click Install.

5. In the Select Network Component Type, dialog box, click Protocol, and then click Add.

6. In the Select Network Protocol dialog box, click Microsoft TCP/IP version

6, and then click OK.

7. Click Close to save changes to your network connection.

8. Alternately, from the Windows XP desktop, click Start, point to Programs, point to Accessories, and then click Command Prompt.

9. At the command prompt, type netsh interface ipv6 install.

For Windows XP with SP1, do the following: For step 6:

6. In the Select Network Protocol dialog box, click Microsoft IPv6 Developer Edition, and then click OK.

For Windows XP with no service packs installed:

1. Log on to the computer running Windows XP with a user account that has privileges to change network configuration.

2. Open a command prompt. From the Windows XP desktop, click Start, point

to Programs, point to Accessories, and then click Command Prompt.

3. At the command prompt, type ipv6 install.

5 IPv6 Exercises

Verifying your configuration For Windows Server 2003, Windows XP with SP2, and Windows XP with SP1, you can use the ipconfig command to view your IPv6 configuration. For example: c:\>ipconfig Windows IP Configuration Ethernet adapter Ethernet: Connection-specific DNS Suffix . : wcoast.corp.example.com

IP Address. . . . . . . . . . . . : 157.54.139.57 Subnet Mask . . . . . . . . . . . : 255.255.252.0 IP Address. . . . . . . . . . . . : 2001:db8:8311:f282:1460:5260:c9b1:fda6 IP Address. . . . . . . . . . . . : 2001:db8:8311:f282:b973:4db8:97e2:e978 IP Address. . . . . . . . . . . . : 2001:db8:8311:f282:200:39ff:fe0e:fc35 IP Address. . . . . . . . . . . . : fec0::f282:200:39ff:fe0e:fc35%1 IP Address. . . . . . . . . . . . : fe80::200:39ff:fe0e:fc35%4

Default Gateway . . . . . . . . . : 157.54.136.1

fe80::210:ffff:fed6:58c0%4 Tunnel adapter 6to4 Tunneling Pseudo-Interface:

Connection-specific DNS Suffix . : wcoast.corp.example.com IP Address. . . . . . . . . . . . : 2002:9d3b:8b39::9d3b:8b39 Default Gateway . . . . . . . . . :

Tunnel adapter Automatic Tunneling Pseudo-Interface:

Connection-specific DNS Suffix . : wcoast.corp.example.com IP Address. . . . . . . . . . . . : fec0::f70f:0:5efe:157.54.139.57%1 IP Address. . . . . . . . . . . . : 2001:db8:8311:f70f:0:5efe:157.54.139.57 IP Address. . . . . . . . . . . . : fe80::5efe:157.54.139.57%2

Default Gateway . . . . . . . . . : fe80::5efe:157.56.253.8%2

For Windows Server 2003, Windows XP with SP2, and Windows XP with SP1, you can also use the netsh interface ipv6 show address command to view your IPv6 addresses. For example: c:\> netsh interface ipv6 show address Interface 4: Ethernet Addr Type DAD State Valid Life Pref. Life Address --------- ---------- ---------- ---------- ----------------------------------- Anonymous Preferred 596758 78191 2001:db8:8311:f282:1460:5260:c9b1:fda6 Anonymous Deprecated 510530 0 2001:db8:8311:f282:b973:4db8:97e2:e978 Public Preferred 2591874 604674 2001:db8:8311:f282:200:39ff:fe0e:fc35 Public Preferred 2591874 604674 fec0::f282:200:39ff:fe0e:fc35 Link Preferred 4294967295 4294967295 fe80::200:39ff:fe0e:fc35 Interface 3: 6to4 Tunneling Pseudo-Interface Addr Type DAD State Valid Life Pref. Life Address --------- ---------- ---------- ---------- ----------------------------------- Other Preferred 4294967295 4294967295 2002:9d3b:8b39::9d3b:8b39

6 IPv6 Exercises

Interface 2: Automatic Tunneling Pseudo-Interface Addr Type DAD State Valid Life Pref. Life Address --------- ---------- ---------- ---------- ----------------------------------- Public Preferred 2591700 604500 fec0::f70f:0:5efe:157.54.139.57 Public Preferred 2591700 604500 2001:db8:8311:f70f:0:5efe:157.54.139.57 Link Preferred 4294967295 4294967295 fe80::5efe:157.54.139.57 Interface 1: Loopback Pseudo-Interface Addr Type DAD State Valid Life Pref. Life Address --------- ---------- ---------- ---------- ----------------------------------- Loopback Preferred 4294967295 4294967295 ::1 Link Preferred 4294967295 4294967295 fe80::1 Testing your configuration using Ping. Windows Server 2003, Windows XP with SP2, and Windows XP with SP1 include an IPv6-enabled version of the ping.exe tool. When you ping a link-local address with the ping.exe tool, you must include a zone identifier (ID) which specifies the interface over which the ICMPv6 Echo Request messages are sent. For link-local addresses, the zone ID is typically equal to the interface index, as displayed in the output of the netsh interface ipv6 show interface command. For site-local addresses, the zone ID is equal to the site number, as displayed in the output of the netsh interface ipv6 show interface level=verbose command. If multiple sites are not being used, a zone ID for site-local addresses is not required. The zone ID is not needed when the destination is a global address. To send ICMPv6 Echo Request messages to the link-local address fe80::260:97ff:fe02:6ea5 using zone ID 4 (the interface index of an installed Ethernet adapter), use the following command:

Note: the Zone id is YOUR interface index ping fe80::260:97ff:fe02:6ea5%4

7 IPv6 Exercises

Exercise 2 IPv6 Subnetting

Subnetting an address in IPv6 is essentially no different from IPv4 subnetting (except of course that there are more bits involved!!) As in IPv4, it is important to think of address as a binary number when subnetting (rather than in HEX or decimal). However, because of the complexity of the large 128 bit address, it is easier to work in 16 bit values using 4 HEX digits for notation. IPv6 address space can therefore be broken into eight columns separated by a colon “:”. Each column contains a 4 HEX digit value and each HEX digit has 4 bit value (16 bits per column which is equivalent to a 2 bytes per column.) In the past IPv6 Global Unicast addressing used the TLA/NLA/SLA format. That format has been replaced by a coordinated policy defined by the Regional Internet Registry (RIRs). This new standard is the IPV6 Addressing Architecture (ARCH ) format (RRC3587). | n bits | m bits | 128-n-m bits | +-------------------------+-----------+----------------------------+ | global routing prefix | subnet ID | interface ID | +-------------------------+-----------+----------------------------+ Current address allocation policy defines up to 64 bits of a global unicast address to be reserved for the network prefix and 64 bits for the interface ID. The network ID will include the global routing prefix (as allocated by the RIR) and the subnet IDs (as defined by the LIR, ISP or end user network operator. An LIR or ISP allocated a /32 block by the RIR can subdivide this block into sub-allocations or end site assignments of up to /64. This implies that the address space between the /32 allocation and the /64 is used for subnetting. Subnetting an IPv6 Address Exercises Given Scenario: An ISP operator has been allocated the following IPv6 address block by APNIC 2001:00AA::/32 Scenario 1 : This ISP has 5 downstream smaller ISP customers and needs to now sub-allocate smaller blocks to these companies. After consideration they decide to allocate /35 blocks. Define the address blocks (prefix and length) for the blocks the ISP allocates. Assume the first /35 block is retained by the ISP for its own purposes.

8 IPv6 Exercises

Block Prefix/length 1 2 3 4 5 6

Scenario 2 : The customer ISP that received the second block allocated by the ISP now needs to assign address space to its end site customers. There are 4 such customers. Identify the /35 block that this customer ISP holds and then define the /48 subnets that are assigned to the end sites ISP Block:_________________________________ Block Prefix 1 2 3 4

Scenario 3 : One of the end sites customers now wishes to assign a series of addresses for point to point connectivity and will use /64 assignments for this.. It needs a set of 5 such configurations. From the /48 that it has been assigned, determine subnetting plan you can use for these point to point connections and then identify the appropriate of /64 subnets for this. block used__________________________ Block Prefix/length 1 2 3 4 5

9 IPv6 Exercises

Scenario 4 Assume one of the hosts on your network has a MAC address of 00:0d:60:89:31:9b What will be the link local address which is generated for this machine? Exercise 3 Introduction to IOS

In this next section you will be introduced to the Cisco Internetworking Operating System (IOS). It is the IOS that runs the Cisco routers and also Cisco switches.

The exercises in this section will cover basic IOS router configuration concepts and commands on order to enable you to build and configure the IPv6 network we will be looking at

Exercise 3.1:

Connect to the router you have been assigned to as instructed in the class.

Router> This indicates you are in USER mode.

Cisco IOS has a command interpreter called the Exec. The Exec first interprets the command you type and then carries out the operation requested. The Exec has two levels of access: user and privileged. These two levels of access are sometimes referred to as modes and serve as a security barrier for access to the different levels of commands.

User mode is used for basic tasks such as checking the router's status, connecting (telnet-ing) to remote devices, making temporary changes to terminal settings, and viewing basic system information. In this mode, the view of the router's configuration and troubleshooting capabilities are very limited, and configuration changes cannot be made.

Privileged mode is used to change the configuration of the router. The commands in privileged mode include all those available in user mode, plus those used to set IOS parameters, get detailed information about the router's status and configuration, test and run debug operations, and to access global configuration modes.

10 IPv6 Exercises

Exercise 3.2:

a) To change to privileged mode, type enable at the prompt. You will need to provide the enable password for this

In privileged mode notice that the prompt has a hash (Router#) instead of an arrow (Router>).

b) To return to user mode, type disable at the prompt.

c) To close the console, just enter logout.

To manually configure a router, you need to be in configuration mode. This can be accessed only from privileged mode. In configuration mode, you have access to configuration commands that will allow you to configure the router as a whole, including the essential commands to set up the interfaces (connections to networks) and to configure routing and routing tables. From this mode you can also view other configuration details and save your configuration.

A router's configuration file is loaded on bootup from NVRAM (Non volatile memory). The configuration loaded is known as the startup-config. Once it is loaded (into RAM) it becomes the running-config. Changes can then be made to the running-config dynamically through configuration mode.

The configuration can also be stored on an external server (for backup) and restored at anytime by loading it from the server using TFTP (Trivial File Transport Protocol). The startup-config can be re-loaded at any time from NVRAM to overwrite the running-config if errors have been made. To enter configuration mode you use the config command. On real routers, there are three sub-modes for config mode:

• Config terminal (config t) executes configuration commands from the terminal (from a console port or telnet) and allows you to dynamically change the running-config. Changes take effect immediately.

• Config memory (config mem) Loads the configuration file (startup-config) stored stored in NVRAM. This will again copy the startup-config to the running-config.

• Config network (config net) is used to retrieve a configuration file stored on a server using TFTP.

11 IPv6 Exercises

Exercise 3.3:

From privileged exec mode, enter configuration mode by typing config t

Helpful IOS features:

You can use a question mark (?) from any prompt to see the list of available commands at that prompt. To find help for a specific command enter the first letter of that command and a question mark without a space in between. For example, router>t? will list all commands beginning with t available from user mode. Use the tab key to finish off commands that you have partially typed. If there is no command ambiguity, the tab key finishes typing for you. The Up and Down arrows are also useful to save retyping commands previously entered.

Exercise 3.4:

Experiment with the help feature. Check out the list of commands at each exec mode. Practice using the tab key, up and down arrows to save yourself typing time.

You can view information about a router (or switch) via the show (sh) command.

Type sh ? to see a list of all the options.

Exercise 3.5:

a. To view basic information about the router use sh version from privileged mode. Examine the output and try and identify some of the information shown.

b. To see the configuration file in NVRAM, enter show startup-config from privileged mode. What do you discover?

c. To see the configuration file in RAM, enter show running-config from privileged mode.

d. From privileged mode type copy run start to copy the running config from RAM into NVRAM. Notice that you do not have to type the complete command (so long as there is no ambiguity).

e. Check the config file in NVRAM again.

Note: It is important to remember to save your running-config to NVRAM after you have made changes. If you forget to do this, once the device reboots, your changes will be lost.

12 IPv6 Exercises

Recall that each network connected to an internetwork must have its own network id (network prefix) in order for routing to be possible between these networks. Remember that a router has multiple interfaces with each one connected to a different network. A router is a device that is on multiple networks.

Exercise 3.6:

The most basic and important element in configuring a router is to configure the interfaces that connect to networks. This is done in global configuration mode. In this mode you are able to enter the configuration mode for each individual interface and set the parameters for the interface. To enter interface configuration mode, specify the type of interface (in this case fast ethernet) and the slot/port number (0/0), by typing:

router(config)#interface fastethernet 0/0 (int f0/)

The prompt changes to show the new mode: Router (config-if)#

You now configure the IP address of this interface:

router(config-if)#ip address <ip address> <netmask>

All interfaces are by default shut down. You can bring up an interface with the no shutdown command. Interface settings will not work until you have turned the interface on:

router(config-if)#no shutdown

Using the following set of commands, configure the Fast Ethernet 0/1 ports on your routers using the IP addresses as shown.

enable ipv6 unicast routing int fastethernet 0/1 ip address 192.168.1.20X 255.255.255.0 ipv6 enable ipv6 address 2001:1234:1::X/48 exit copy run start

where X is the number of the router you have been allocated

13 IPv6 Exercises

Since all the routers have been configured with the same network prefixes and are connected to the same switch, you can ping from one router to the other using either the IPv4 or IPv6 addresses.

In order to examine the current running-configuration of your router, click on the router to access the console and then from user mode, type:

show run

In order to check entries in the router's routing table, the sh ip route command is accessed from privileged mode, by typing:

show ip route

14 IPv6 Exercises

Exercise 4 IPv6 IX topology In this exercise we will expand on the configuration we have done in exercise 3 and simulate the construction of an IX An IX provides a peering exchange where ISPs and other providers can connect together in order to route traffic between themselves by mutual agreement without cost. Each IX member network or AS maintains a presence in the IX through a router which acts as a border router to the other networks (ASs ) in the IX. The routers are commonly connected to a switch on a common vlan providing them with the peering connectivity. In this exercise you will: Determine the IP addressing scheme for the IX and for your ISP lan network Configure the external interfaces of the routers connecting your ISP to the IX Configure static routing on these interfaces Configure an internal lan for your ISP Configure BGP on the router Test this connectivity. You will be be working with a partner in this configuration and will be assigned a router from the list below IPv6 network topology IX Subnet: 2001:00AA::/48 Router 2: 2001:abc2::/32 Router 7: 2001:abc7::/32 Router 3: 2001:abc3::/32 Router 8: 2001:abc8::/32 Router 4: 2001:abc4::/32 Router 9: 2001:abc9::/32 Router 5: 2001:abc5::/32 Router 10: 2001:abca::/32 Router 6: 2001:abc6::/32

15 IPv6 Exercises

Exercise 4.1 Using the address block assigned to the IX create a subnet from the IX /48 block for the network connecting all the IX members together. Assign interface addresses to these routers from this subnet. Select the first /64 for this. Exercise 4. 2 Each of the ISPs have been allocated a /32 address. From this block define /48 subnet for an internal LAN segment for this ISP Router no.

Router no.

R 2 R 7 R 3 R 8 R 4 R 9 R 5 R 10 R 6

IXP Diagram

R7

R10

R9

R8

R2

R3 E0/0

E0/0

E0/0

E0/0

E0/0

E0/0

FE0/0

FE0/0

FE0/0

R4

R5

R6

R1

S1

16 IPv6 Exercises

Exercise 4.3 From this /48 address assign an address to the internal interface of the ISP router. The E 0/0 or F 0/0 interfaces connect to the IX, so the E0/1 or F0/1 interface will be internal interface Router no.

Internal Interface Router no.

Internal Interface

R 2 R 7 R 3 R 8 R 4 R 9 R 5 R 10 R 6 Configuring the interfaces 1. Configuring router interface with IPv6 address.

The router has several different interfaces, which are required to be configured Assume we are configuring the e0/0.

1. Select the appropriate interface required prior to configuration. 2. Once selected ensure that the interface is up. Issue the command “show

interface”

Myrouter # show interface e0/0

3. Choose the interface to be configured and provide the IP Address to it. Example: Eth0 configuration

Myrouter # configure terminal Myrouter(config) # interface e0/0 Myrouter(config-if) #

4. Configure the IP address for the interface selected.

Example: e0/0 configuration with a /64 subnet

Myrouter(config-if) # ipv6 address ipv6 address/prefix size in CIDR

Myrouter(config-if) # ipv6 address 2001:AA::1/64

5. Enable IPv6 on the interface selected.

Example: e0/0

17 IPv6 Exercises

Myrouter(config-if) # ipv6 enable

6. Exit from the interface configuration and enable IPv6 Unicast datagram forwarding by typing the command below.

Myrouter(config) # ipv6 unicast-routing

7. Save the configuration by issuing the command: “copy run start”

Exercise 4.4 Configure static routes for the IPv6 ISP networks. For each network connected to an IX member ISP, we configure a static route on the other routers

Myrouter(config)ipv6 route destination network/prefix <outbound interface or next hop IP address>

Myrouter(config)ipv6 route 2001:AA::/35 2001:AA::1 We will define this list together in the workshop

Exercise 4.5 Configure BGP with the IPv6 address.

Remove the static route configuration, before proceeding to BGP.

Myrouter(config) no ipv6 route 2001:AA::/48 You will need to complete this to remove each route

Type “router bgp” with the AS number in the command prompt of the router user exec mode to configure the bgp protocol.

router#configure terminal router(config)#router bgp <ASN> router(config-router)#no auto summary router(config-router)#no synchronization

Where the AS number is the number of your router

18 IPv6 Exercises

Type the statement for the networks that will be announced within the your AS.

router(config-router)# network ipv6network/prefix size)

1. Configure the neighbor peering pointing to the neighbor interface IP address.

router(config-router)# neighbor <other ASN interface IP> remote-as <other ASN>

Sample Configuration ==================== router#configure terminal router(config)#router bgp 1 router(config-router)# no auto-summary router(config-router)# no synchronization router(config-router)# network 2001:abcd::/64 router(config-router)# neighbor 2001:abcd:1234:abc1::1 remote-as 2 (for peering with other network)

Verifying the BGP process

1. Verify that the configuration for the routing process is working properly by

typing the commands below:

show ipv6 bgp summary (to check the bgp summary table) sh ipv6 bgp neighbour (to check neighbour list) sh ipv6 route (to check the routing table for the BGP announcement)

19 IPv6 Exercises

Exercise 5 IPv6 Tunneling Topology This exercise will demonstrate the tunnelling of IPv6 traffic from a number of IPV6 enabled ISPs through an IPv4 core. There are 3 network types involved: IPv6 network AS2, AS6, AS8 Dual stack network AS4, AS5, AS7 IPv4 network AS3 In the workshop you will be allocated to a team that will configure an ISP IPv6 network and the corresponding dual stack network. A team will also configure the IPv4 network router. For the layout please see the diagram below: For this exercise you will use addresses from the IPv6 block: 2001:aaaa::/32 and from the IPv4 block: 192.168.0.0

20 IPv6 Exercises

Exercise 5.1 For each of the IPv6 networks assign a /48 from the given block For each of the IPv4 networks assign a /24 from the given block. Exercise 5.2 Refer back to the previous exercise for the appropriate command syntax Configure appropriate IPv6 addresses on both interfaces of the IPv6 AS routers Configure both an IPv6 address and an IPv4 address on the interface connecting the dual stack routers to the IPv6 AS. Configure a IPv4 address on the interface of the dual stack routers connecting the dual stack routers to the IPv4 network Configure IPv4 addresses to the interfaces of the core router.

ISP Network Diagram

FE0/0

R5

E0/0

E0/1

E0/0

E0/1 E1/0

FE0/0

FE0/1

E0/0

E0/0

E0/1

E0/0

AS2

AS4

AS3

AS5

AS6

AS7

AS8

R2

R4

R3

R5 R7

R8 R6

E0/1

E0/1

E0/1

21 IPv6 Exercises

Exercise 5.3 Configure tunnels between the dual stack routers and the core A tunnel is configured on the dual stack router as a next hop address to the IPv6 destination network. A IPv6 route to that network is then configured using the tunnel as the next hop. config t interface Tunnel 1 ipv6 unnumbered e0/1 tunnel source e0/1 tunnel destination <the IPv4 interface of the dual stack router that connects to the target IPv6 network> tunnel mode ipv6ip

A route is now defined to the IPv6 network using the tunnel as the next hop address. ipv6 route <target IPv6 network> <tunnel ID> Appropriate static routes will also need to be configured Exercise 5.4 Configure BGP Remember to remove static routes. For the IPv6 networks you need to announce the networks in the AS. You must also ensure that your IPv4 network is well connected. This means ensuring that you have dynamic routing appropriately configured on the IPv4 routers ( or you have configured static routes)

On the IPv6 network routers:

router#configure terminal router(config)#router bgp <ASN> router(config-router)#no auto summary router(config-router)#no synchronization

Type the statement for the networks that will be announce within the AS. router(config-router)# network ipv6network/prefix size

For all the routers you need to configure neighbor peering

22 IPv6 Exercises

Configure the neighbor peering pointed to the neighbor interface IP address.

router(config-router)# neighbor <other ASN interface IP> remote-as <your ASN>

Sample Configuration ==================== router#configure terminal router(config)#router bgp 1 router(config-router)# no auto-summary router(config-router)# no synchronization router(config-router)# network 2001:abcd::/64 (for the /64 network aggregate) router(config-router)# neighbor 2001:abcd:1234:abc1::1 remote-as 1 (for peering with other network)

Exercise 5.5 Verifying BGP process

1. Verify the configuration if the routing process is working properly by typing the

commands below:

show ipv6 bgp summary (to check the bgp summary table) sh ipv6 bgp neighbour (to check neighbour list) sh ipv6 route (to check the routing table for the BGP announcement)