FAQ : Connectivity (Tunnels and Subnets) : How do I give connectivity to other hosts on my subnet?

FAQ Item
- SixXS Prefixes
- What is a "site"?
- Operating System configuration

How do I give connectivity to other hosts on my subnet?

Per default every tunnel has a routed /64, the so-called "Default Subnet". This subnet is routed towards the <tunnel>::2 address and is directly available for connecting hosts on a separate link behind the tunnel. If one has multiple network segments that require a /64 behind the tunnel (eg wired, wireless, DMZ, etc) one will need to request a Full Subnet (/48).

You can find your subnets in your User Home.

The easiest way to use your subnet is to assign a /64 per switch network and then setup a Router Advertisement server. As SixXS serves out a /64 per default (Default Subnet) and a /48 (Full Subnet) on request you either have 1 /64 and in the case of the /48 the possiblity of having 65535 /64's and thus subnets inside your site.

A /48 is an end-site and should thus not be delegated to another administration. In case you want to connect multiple sites under different administration we suggest using multiple tunnels and subnets, unless of course the network is the same. See also the definition of a site below.

SixXS Prefixes

In the SixXS system three types of prefixes exist:

Type	Description
Tunnel	/64	Only tunnel::1 (PoP) and tunnel::2 (User Endpoint) are used
Default Subnet	/64	Routed towards tunnel::2, can be used to do Router Advertisement on one directly connected network behind the tunnel. Per default routed towards the tunnel
Full Subnet	/48	Routed towards tunnel::2, can be used to attach 65536 networks of each /64 behind the tunnel. Needs to be requested through the webinterface

Note thus that the user cannot use any other addresses but tunnel::2 for the tunnel prefix.

What is a "site"?

A site is defined as a network with one single administration. The moment a change occurs in administration, one is in a different site. Thus if you have one network operated by administration group X and another network operated by admin Y then those are two sites. Of course, when group X and Y, both administratively fall under group A, they can still be taken as to be a single site.

Operating System configuration

Under Linux the Router Advertisement (RA) server is called radvd, *BSD (KAME stack) calls it rtadvd. Clients can then be configured using RFC 2462 aka "IPv6 Stateless Address Autoconfiguration".

AIX - Router and Host

From the AIX 5.3 documentation.

To enable IPv6 router functionality

Open the /etc/rc.tcpip file in your favorite text editor.

Uncomment the following line in that file:

# Start up autoconf6 process
start /usr/sbin/autoconf6 ""

Add the following lines immediately after the line that you just uncommented in the previous step:
```
# Configure global addresses for router
ifconfig en0 inet6 2001:db8:aaaa::/64 eui64 alias
ifconfig en1 inet6 2001:db8:bbbb::/64 eui64 alias
```
In this scenario, our network has only two subnets, en0 and en1. You will need to add a line to this file for every subnet that your router is sending packets to.

Uncomment the following line in the file:

# Start up ndpd-router daemon
start /usr/sbin/ndpd- router "$src_running"

When you reboot, IPv6 will be automatically started. To do it directly, execute those two lines in your shell.

Set up IPv6 to be configured on the hosts at boot time

Open the /etc/rc.tcpip file using your favorite text editor.

Uncomment the following lines in that file:

# Start up autoconf6 process
start /usr/sbin/autoconf6 ""

# Start up ndpd-host daemon
start /usr/sbin/ndpd-host "$src_running"

When you reboot, your IPv6 configuration will be set. To do it directly, execute those two lines in your shell.