HP OpenVMS systems documentation

After installing TCP/IP Services, you can configure your system to communicate in an IPv6 network environment by performing the tasks described in this chapter.

You can configure your node as either an IPv6 host or IPv6 router. You make this choice while running the TCPIP$IP6_SETUP configuration utility. After you run the configuration utility and restart TCP/IP Services, IPv6 processes associated with your choices are started on your system.

2.1 IPv6 Processes

Your selection of configuring your node as either a host or a router starts one of the following processes during TCP/IP startup:

• TCPIP$ND6HOST (host process)
• TCPIP$IP6RTRD (router process)

The TCPIP$ND6HOST process receives and processes IPv6 router advertisement (RA) packets of the neighbor discovery protocol. This enables a system to autoconfigure itself without manual intervention.

The TCPIP$ND6HOST process performs the following functions, based on the contents of IPv6 router advertisements it receives:

• Router discovery---Learns the IPv6 address of default routers and installs default routes in the kernel routing table.
• On-link prefix discovery---Learns IPv6 on-link prefixes (ranges of IPv6 addresses that are directly reachable on a given link).
• Stateless address configuration---Automatically creates and deletes interface addresses.
• Interface attribute configuration---Automatically configures datalink attributes, such as hop limit, reachable time, retransmit time, and link MTU.

After you configure the system as an IPv6 router, the TCPIP$IP6RTRD process sends out periodic router advertisements for the following reasons:

• To advertise itself as a potential default router for IPv6 traffic. The IPv6 hosts on the link receive these advertisements as part of their neighbor discovery processing.
• To advertise an IPv6 address prefix, in which case hosts on the link perform address autoconfiguration.

At startup, the TCPIP$IP6RTRD process reads its configuration file for startup information. See Section 2.6.2 for more information on the router configuration file.

2.2 Preparing for Configuration

Before you configure the network software, you must gather information about your system and network environment. The Configuration Worksheet shown in Figure 2-1 can help you assemble this information in an orderly fashion. The following sections describe the information that you need to record on the worksheet.

Figure 2-1 Configuration Worksheet

1. IPv6 Configuration
   • IPv6 router
     If you want this system to function as an IPv6 router, check Yes; otherwise, check No. If you check No, the system is configured as an IPv6 host.
     An IPv6 router can advertise address prefixes to all hosts on connected links (for example, a LAN and a configured tunnel) and can forward packets to their destinations. Packets can be forwarded directly on link or over IPv4 tunnels.
   • DNS/BIND automatic updates (hosts only)
     If you want this system to record its addresses in the DNS/BIND database automatically, check Yes; otherwise, check No. If you check Yes, you must configure your system as a DNS/BIND client and your DNS/BIND server must support dynamic updates to the DNS database. See Chapter 3 for information on configuring your DNS/BIND server.
   • IPv6 interfaces
     Enter the device names of the network interface to the IPv6 network. For example, WE0 and WF0. If you are creating a configured tunnel only on your system, enter None.
   • 6to4 tunnel
     If you want IPv6 to run over a 6to4 tunnel, check Yes; otherwise, check No. A 6to4 tunnel has one source and one destination in an IPv4 network.
   • Configured tunnel
     If you want IPv6 to run over a configured IPv4 tunnel, check Yes; otherwise, check No. A configured tunnel has one source and one destination in an IPv4 network. You should use configured tunnels instead of automatic tunnels. You can configure multiple configured tunnels.
   • Automatic tunnel
     If you want to configure IPv6 to run over IPv4 automatic tunnels, check Yes; otherwise, check No.

     Note Do not use automatic tunnels in production environments. Their use might be deprecated in the future.

   • Manual routes
     If you want to configure manual routes to other systems, check Yes; otherwise, check No.
     On a router, you might want to configure manual routes if one of the following conditions is true:
     • You want a configured tunnel and you are not advertising an address prefix on the tunnel link.
     • You want a configured tunnel and the router at the other end of the tunnel is not running the RIPng protocol.
     • Your system is not running the RIPng protocol.
     
     On a host, you might want to configure manual routes if you want a configured tunnel to a router and the router is not advertising itself as a default router on the tunnel link.

   • Start IPv6
     If you want the IPv6 initialization script executed from the configuration utility, check Yes. If you want the initialization script executed during the next system boot, check No.
2. DNS/BIND
   • Domain name
     The fully qualified domain name for your node. This consists of the host name and the DNS/BIND domain name (for example, host1.subdomain.example ).
3. 6to4 Tunnel
   • Host address
     Your node's name or IP address (this end of the tunnel).
   • Site prefix
     The TCPIP$IP6_SETUP command procedure automatically generates a 48-bit 6to4 site prefix.
   • Address prefix (hosts only)
     If your system is an IPv6 host, enter a 64-bit 6to4 prefix to be configured on the 6to4 tunnel interface. The upper 48 bits of the address prefix must be identical to the site prefix generated by the TCPIP$IP6_SETUP command procedure.
   • Relay router address
     If you want to communicate with an IPv6-only network, enter the 6to4 address of the relay router.
4. Configured Tunnel
   • Type
     The type of configured tunnel. Valid types are IPv4 and IPv6.
   • Interface
     The name of the configured tunnel interface. For example, IT0.
   • Destination address
     The remote node's address (the remote end of the tunnel).
   • Source address
     Your node's address (this end of the tunnel).
   • RIPng
     If your system is a router and you want the router to run the RIPng protocol on the tunnel link to exchange IPv6 routing information with a router at the remote end of the tunnel, check Yes; otherwise, check No.
   • Address prefix
     If your system is a router and you want to advertise address prefixes to the node at the remote end of the tunnel, enter a 64-bit prefix; otherwise, write Done. If your system is an IPv6 host and the router at the remote end of the tunnel is not advertising an address prefix, enter a 64-bit prefix to be configured on the tunnel interface.

5. Router
   • Interface
     The name of the interface (LAN or configured tunnel) on which you want to run the RIPng protocol or advertise an address prefix.
   • RIPng
     If you want the router to run the RIPng protocol on the specified interface and to exchange IPv6 routing information with other routers on the link (LAN or configured tunnel), check Yes; otherwise, check No.
   • Address prefix
     If you want to advertise address prefixes to all hosts on the link, enter a 64-bit prefix; otherwise, write Done. If you do not specify a 64-bit prefix, the router will not advertise an address prefix. All hosts must obtain their prefix information from another source.
     Prefixes in IPv6 define a subnet and are typically configured on a router for a specific link by the network administrator. The router advertises this prefix to all nodes connected to that link, along with the length of the prefix, whether the prefix is on link (that is, a neighbor), whether the prefix can also be used for stateless address configuration, and the length of time the prefix is valid.
6. Manual Routes
   • Destination prefix
     The address prefix of a remote IPv6 network. The address prefix contains a Classless Inter-Domain Routing (CIDR) style bit length, for example, 5F00::/8. If you want to use the default route, write Default.
   • Interface
     The name of the interface through which you are sending traffic to the remote IPv6 network.
   • Next hop address
     The IPv6 address of the first router in the path to the destination prefix. Write the link local address of the router. If the connection to the router is over an IPv4 tunnel, write the link local IPv6 address of the remote tunnel endpoint.

When you run the TCPIP$IP6_SETUP command procedure, it gathers information from the system and prompts you for additional configuration information. See Section 2.4 for more information on running the TCPIP$IP6_SETUP command procedure.

2.3 IPv6 System Configuration Examples

This section shows how to use the configuration worksheet to assemble information for selected configurations. Each example shows how individual systems are configured. In some cases, additional options for you to consider are provided.

In a simple host-to-host configuration (shown in Figure 1-11), host A and host B use IPv6 link-local addresses. By default, the TCPIP$IP6_SETUP command procedure configures the hosts automatically with a link-local address for your system. Figure 2-2 shows the completed worksheet for host A.

Figure 2-2 Simple Host-to-Host Configuration

After you configure IPv6 on host A, add a link-local address for host B to the TCPIP$ETC:IPNODES.DAT file. The configuration process for host B in this configuration is similar to that for host A.

In this configuration, no global address prefix is advertised on the LAN. If you want to advertise a global address prefix, you can either configure one of the hosts as a router by using TCPIP$IP6_SETUP or add an IPv6 router to the LAN configuration. An IPv6 router advertises a global prefix on the link.

You can use the netstat -in command to view a local node's link-local and global addresses.

The following TELNET command connects host A to host B using host B's link-local address:

$ TELNET fe80::0a00:2bff:fee2:1e11

Alternately, you can place the address and node name in the TCPIP$ETC:IPNODES.DAT file. Then use the node name as the argument to the TELNET command.

2.3.2 Host-to-Host with Router Configuration

In a host-to-host with router configuration (shown in Figure 1-12), host A and host B are on a LAN with router A. In this case, router A advertises the global address prefix dec:1:1::/64 on the LAN. Host A and host B use this address prefix to create global IPv6 addresses. (See Chapter 1 for information about obtaining experimental testing addresses.) Figure 2-3 shows the completed worksheet for router A.

Figure 2-3 Host-to-Host with Router Configuration

After you configure IPv6 on router A, add the global addresses for the other hosts to the TCPIP$ETC:IPNODES.DAT file. Repeat this step on host A and host B. Alternatively, you could establish DNS/BIND in your network using the global addresses.

2.3.3 IPv6 Network-to-IPv6 Network with Router Configuration

Figure 2-4 IPv6 Network-to-IPv6 Network with Router Configuration

In this example configuration (shown in Figure 1-14), four IPv6 networks are connected to each other using three routers. In this configuration, the routers must exchange routing information in order to learn the routes to other subnets in the network. To accomplish this, each router must run the RIPng protocol. Figure 2-5 shows the completed worksheet for router A.

Figure 2-5 Multiple IPv6 Networks and Multiple Routers Configuration

The completed worksheets for router B and C would be similar.

2.3.5 Host-to-Host over IPv4 Configured Tunnel Configuration

In a host-to-host over tunnel configuration (shown in Figure 1-15), two IPv6 systems communicate with each other over a configured tunnel through an IPv4 network and use IPv6 link-local addresses. Figure 2-6 shows the completed worksheet for host A.

Figure 2-6 Host-to-Host over IPv4 Configured Tunnel Configuration

After you configure IPv6 on host A, add the link-local address for host B to the TCPIP$ETC:IPNODES.DAT file. The configuration process for host B in this configuration is similar to that for host A.

With this configuration, no global address prefix is advertised on the tunnel. If you want to advertise a global address prefix, you can configure one of the hosts as a router by using TCPIP$IP6_SETUP. An IPv6 router advertises a global prefix on the link.

To view a local node's link-local and global addresses, use the netstat -in command.

The following TELNET command connects host A to host B:

$ telnet fe80::5.6.7.8

Alternately, you can place the address and node name in the TCPIP$ETC:IPNODES.DAT file. Then use the Node name as the argument to the TELNET command.

2.3.6 Host-to-Router over IPv4 Configured Tunnel Configuration

In a host-to-router over tunnel configuration (shown in Figure 1-16), host X communicates with host B over a configured tunnel through an IPv4 network; both nodes use IPv6 addresses. The tunnel in this case is between host X and router A. Figure 2-7 shows the completed worksheet for host X when router A is advertising itself as the default router for the tunnel link and is advertising a global address prefix on the tunnel link.

Figure 2-7 Host-to-Router over IPv4 Configured Tunnel Configuration

If router A is not advertising a global address prefix on the tunnel link, the value dec:3:1::/64 would be in the Address prefix field in the Configured Tunnel section of the host X worksheet. If router A is not advertising itself as the default router for the tunnel link, the information shown in Figure 2-8 would also be on the host X worksheet:

Figure 2-8 Router Not Advertising a Global Address Prefix

Figure 2-9 shows the completed worksheet for router A when router A is advertising a global address prefix on the tunnel link.

Figure 2-9 Router Advertising a Global Address Prefix

If router A is not advertising a global prefix on the tunnel link, the information shown in Figure 2-10 would be on the router A worksheet. Note the manual route to host X. Instead of specifying a destination network prefix, you specify the host route, dec:3:1::5.6.7.8 , to host X. The next hop is the link-local IPv6 address of host X's tunnel interface, fe80::5.6.7.8 .

Figure 2-10 Router A Not Advertising a Global Prefix on the Tunnel Link

In an IPv6 to IPv6 network over tunnel configuration (shown in Figure 1-17), host A communicates with host F over a configured tunnel through an IPv4 network. The host configuration is similar to that of host A Section 2.3.1. All hosts automatically use their default router in order to communicate with hosts on other networks. Figure 2-11 shows the worksheet for router A.

Figure 2-11 IPv6 Network to IPv6 Network over IPv4 Configured Tunnel Configuration

You do not have to run RIPng on the WE0 and WE1 interfaces because no routers are attached to the interfaces.

The configuration of router B is similar, except that the source and destination addresses for the configured tunnel would be switched and the address prefixes advertised on WE0 and WE1 would be dec:2:1::/64 and dec:2:2::/64 , respectively.

In a 6to4 tunnel configuration (shown in Figure 1-18), host E is the only node in a 6to4 site. It communicates with host B over a 6to4 tunnel through an IPv4 network: both nodes use IPv6 6to4 addresses. The tunnel in this case is betwen host E and router B. IPv6 is not configured on the host E physical interface because it is connected to an IPv4 network. IPv6, however, is configured on the 6to4 tunnel. Figure 2-12 shows the worksheet for host E.

Figure 2-12 6to4 Tunnel Host E Configuration

Router B is the border router for another 6to4 site, and is also the IPv6 router for that site. Router B is advertising a 6to4 prefix on each subnet. The upper 48 bits of each 6to4 prefix are identical to the 6to4 site prefix. Figure 2-13 shows the worksheet for router B.

Figure 2-13 6to4 Tunnel Router Configuration

Figure 2-14 shows the worksheet for host B. Because router B is advertising a 6to4 address prefix on the subnet, host B autoconfigures its own 6to4 address as part of its participation in the site; it does not need to configure any 6to4 tunnel interfaces.

Figure 2-14 6to4 Tunnel Host B Configuration

You can configure your system as either an IPv6 host or an IPv6 router. In either case, you perform the following steps:

1. Configure your IPv4 stack through the menu-driven TCPIP$CONFIG configuration procedure. This procedure is described in the HP TCP/IP Services for OpenVMS Installation and Configuration manual.

   Note Add the following line to your LOGIN.COM file: $ @SYS$MANAGER:TCPIP$DEFINE_COMMANDS.COM This command procedure defines the UNIX management utilities as foreign commands. Rerun your LOGIN.COM to make the definitions effective for the current process.

2. Run the TCPIP$IP6_SETUP command procedure, described in Section 2.5 and Section 2.6, to configure your system as an IPv6 host or router.
3. Shut down TCP/IP Services and then restart it to enable IPv6.
4. Perform additional configuration tasks depending on whether you've configured your system as a host or router.

Once you have completed configuring your system as either an IPv6 host or router, you can optionally configure your system as a BIND server (described in Chapter 3) or as a correspondent node to support mobile IPv6, described in Chapter 5.

You may want to make other changes to your IPv6 configuration after initial setup. Chapter 4 describes how to make further changes.

2.5 Configuring an IPv6 Host

Before running the TCPIP$IP6_SETUP command procedure, make sure that you have configured your system for IPv4 by running TCPIP$CONFIG.

2.5.1 Run TCPIP$IP6_SETUP to Configure Host

To configure your system as an IPv6 host, do the following:

1. Invoke the TCPIP$IP6_SETUP command procedure by entering the following command:

   $ @SYS$MANAGER:TCPIP$IP6_SETUP

   
   The utility displays information about the IPv6 network configuration procedure and tells you that you can configure the system as either an IPv6 host or an IPv6 router.

2. Choose to configure the system as an IPv6 host by responding to the following prompt:

   Configure this system as an IPv6 router? [NO]:

   
   Press Return to configure the system as an IPv6 host.

3. Indicate whether you want to configure a 6to4 interface:

   Configure a 6to4 interface? [NO]:

   
   A 6to4 interface is needed only if the node is an isolated host with no connection to an IPv6 network.
   Press Return if you do not want to configure a 6to4 interface. The procedure goes to step 8.
   Enter Y and press Return, if you want to configure a 6to4 interface. You'll be prompted to enter information about the interface in subsequent steps.

4. Enter the node's IPv4 address in response to the following prompt:

   Enter this node's IPv4 address:

   
   When you enter your node's IPv4 address and press Return, an IPv6 address prefix is automatically generated and displayed.

5. You are prompted to enter the address prefix for the 6to4 tunnel:

   Enter the address prefix to use on TNn:

   
   Press Return to enter the IPv6 address prefix generated in the previous step.

6. Indicate whether you want this node to connect to native IPv6 sites:

   Connectivity to native IPv6 sites? [NO]:

   
   A relay router is needed to connect your system to native IPv6 sites. If a relay router is not specified, your system can connect to other 6to4 sites but not to native IPv6 sites.
   If you do not want your system to connect to native IPv6 sites, press Return. The procedure goes to step 8.
   If you want your system to connect to native IPv6 sites, enter Y and press Return.

7. Indicate the address of a relay router:

   Enter 6to4 address of a 6to4 Relay Router [2002:C058:6301::]:

   
   The address of the default relay router is displayed. Press Return to use the default, or enter another 6to4 relay router address, and then press Return. The procedure goes to step 8.

8. Answer the prompts about configuring each interface on your system. The procedure displays the following questions:

   Do you want to enable IPv6 on this interface? Enable IPv6 on interface WE0? [YES]:

   
   Press Return if you want to enable IPv6 on this interface; enter N if you do not.
   If your system has multiple interfaces, the procedure repeats this questions for each interface.

9. Indicate whether you want to configure an automatic tunnel by responding to the following prompt:

   Configure an IPv6 over IPv4 automatic tunnel interface? [NO]:

   
   If you want to configure an automatic tunnel, enter Y and press Return; if not, press Return.

10. Indicate whether you want to create a configured tunnel or additional configured tunnels by responding to the following prompt:

    Create a configured tunnel? [NO]:

    
    If you want to create a configured tunnel, enter Y and press Return. You will be prompted for source and destination addresses in steps 11 and 12.
    If you do not want to create a configured tunnel or if you have finished adding a series of configured tunnels, press Return. The procedure goes to step 14.

11. If you chose to create a configured tunnel, enter the tunnel's source IPv4 address in response to the following prompt:

    Source IPv4 address of tunnel IT0?:

    
    Enter an IPv4 address in the standard format ( xx.xx.xx.xx ) and press Return.

12. Enter the tunnel's destination IPv4 address in response to the following prompt:

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