If you plan to configure a 6to4 tunnel from a router or host endpoint, you must advertise the 6to4 site prefix in the /etc/inet/ndpd.conf file on the endpoint system. For an introduction and tasks for configuring 6to4 tunnels, refer to How to Configure a 6to4 Tunnel.
The next figure shows the parts of a 6to4 site prefix.
The next figure shows the parts of a subnet prefix for a 6to4 site, such as you would include in the ndpd.conf file.
This table explains the parts of a 6to4 subnet prefix, their respective lengths, and their definitions.
Part |
Length |
Definition |
---|---|---|
Prefix |
16 bits |
6to4 prefix label 2002 (0x2002). |
IPv4 address |
32 bits |
Unique IPv4 address that is already configured on the 6to4 interface. For the advertisement, you specify the hexadecimal representation of the IPv4 address, rather than the IPv4 dotted-decimal representation. |
Subnet ID |
16 bits |
Subnet ID, which must be a value that is unique for the link at your 6to4 site. |
When an IPv6 host receives the 6to4-derived prefix by way of a router advertisement, the host automatically reconfigures a 6to4-derived address on an interface. The address has the following format:
prefix:IPv4-address:subnet-ID:interface-ID/64 |
The output from the ifconfig -a command on a host with a 6to4 interface might resemble the following:
qfe1:3: flags=2180841<UP,RUNNING,MULTICAST,ADDRCONF,ROUTER,IPv6> mtu 1500 index 7 inet6 2002:8192:56bb:9258:a00:20ff:fea9:4521/64 |
In this output, the 6to4-derived address follows inet6.
This table explains the parts of the 6to4-derived address, their lengths and the information they provide.
Address Part |
Length |
Definition |
---|---|---|
prefix |
16 bits |
2002, which is the 6to4 prefix |
IPv4-address |
32 bits |
8192:56bb, which is the IPv4 address, in hexadecimal notation, for the 6to4 pseudo-interface that is configured on the 6to4 router |
subnet-ID |
16 bits |
9258, which is the address of the subnet of which this host is a member |
interface-ID |
64 bits |
a00:20ff:fea9:4521, which is the interface ID of the host interface that is configured for 6to4 |