Setting up tunneling in IPv6

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You can use either of two methods to set up tunneling in IPv6. The first method sets up an automatic tunnel. The second method sets up a configured tunnel.

Things to Consider

The information in this how-to scenario was tested using specific versions of AIX. The results you obtain might vary significantly depending on your version and level of AIX.

Set up an automatic tunnel in IPv6

In this scenario, the autoconf6 command will be used to configure IPv6 and set up an automatic tunnel through the primary interface, en2. The autoconf6 command will then be used to configure a tunnel through the secondary interface, en0.

Following is the result of the netstat -ni command, which displays the current network configuration of the system:

en0   1500  link#2      MAC address here         0     0       33     0     0
en0   1500  1.1         1.1.1.3                  0     0       33     0     0
en2   1500  link#3      MAC address here     79428     0      409     0     0
en2   1500  10.1        10.1.1.1             79428     0      409     0     0

To enable IPv6 and one automatic tunnel, type the following command:

autoconf6

Running the netstat -ni command now produces the following results:

# netstat -in
en0   1500  link#2      MAC address here         0     0       33     0     0
en0   1500  1.1         1.1.1.3                  0     0       33     0     0
en0   1500  fe80::204:acff:fe49:4910             0     0       33     0     0
en2   1500  link#3      MAC address here     79428     0      409     0     0
en2   1500  10.1        10.1.1.1             79428     0      409     0     0
en2   1500  fe80::220:35ff:fe12:3ae8
sit0  1480  link#7      10.1.1.1                 0     0        0     0     0
sit0  1480  ::10.1.1.1

If en2 (IP address 10.1.1.1) is the primary interface, address ::10.1.1.1 is now available for automatic tunneling over the en2 interface.

To enable an automatic tunnel through interface en0, type the following command:

autoconf6 -s -i en0

Running the netstat -ni command now produces the following results:

# netstat -in
en0   1500  link#2      MAC address here         0     0       33     0     0
en0   1500  1.1         1.1.1.3                  0     0       33     0     0
en0   1500  fe80::204:acff:fe49:4910             0     0       33     0     0
en2   1500  link#3      MAC address here     79428     0      409     0     0
en2   1500  10.1        10.1.1.1             79428     0      409     0     0
en2   1500  fe80::220:35ff:fe12:3ae8
sit0  1480  link#7      1.1.1.3                  0     0        3     0     0
sit0  1480  ::10.1.1.1                           0     0        3     0     0
sit0  1480  ::1.1.1.3                            0     0        3     0     0

This action causes an IPv4-compatible IPv6 address to be added to the existing SIT interface, sit0. Tunneling is now also enabled for interface en0 using address ::1.1.1.3. The same interface, sit0, will be used for both tunnels.

Note: The automatic tunnels are deleted when the system is restarted. To have the automatic tunnel present at boot time, add the required arguments to the autoconf6 command in the /etc/rc.tcpip file.

Set up configured tunnels

In this scenario, SMIT will be used to set up a configured tunnel. This tunnel will be available when the system restarts because it will be stored in the ODM. A tunnel will be configured between systems alpha and beta. The IPv4 address of alpha is 10.1.1.1, and the IPv4 address of beta is 10.1.1.2.

To set up configured tunnels, follow these steps:

To configure a tunnel between alpha and beta, type the following on both systems:
```
smit ctinet6
```
Select Add an IPV6 in IPV4 Tunnel Interface on both systems.
```
autoconf6
```

In this scenario, we filled in the values as follows on alpha, based on the IPv4 addresses:

* IPV4 SOURCE ADDRESS (dotted decimal)               [10.1.1.1]
* IPV4 DESTINATION ADDRESS (dotted decimal)          [10.1.1.2]
  IPV6 SOURCE ADDRESS (colon separated)              []
  IPV6 DESTINATION ADDRESS (colon separated)         []

On beta, the following values were entered:

* IPV4 SOURCE ADDRESS (dotted decimal)               [10.1.1.2]
* IPV4 DESTINATION ADDRESS (dotted decimal)          [10.1.1.1]
  IPV6 SOURCE ADDRESS (colon separated)              []
  IPV6 DESTINATION ADDRESS (colon separated)         []

To view the configured interfaces, type the following command:

ifconfig ctiX

where X is the number of the interface. In this scenario, the following results were returned. On alpha:

cti0: flags=8080051<UP,POINTOPOINT,RUNNING,MULTICAST>
        inet6 fe80::a01:101/128 --> fe80::a01:102

On beta:

cti0: flags=8080051 <UP,POINTOPOINT,RUNNING,MULTICAST>
        inet6 fe80::a01:102/128 --> fe80::a01:101

SMIT automatically creates IPv6 addresses for both ends of the tunnel using the following method:

The lower 32 bits contain the IPv4 address
The upper 96 bits contain the prefix fe80::/96

You can fill in specific IPv6 addresses if desired.