As with native IPv6 routers, you must advertise the subnet prefixes derived from the site 6to4 prefix in /etc/inet/ndpd.conf. The next figure shows the parts of a prefix for a 6to4 site, as described in 6to4 Prefix Format and 6to4 Advertisement Example.
The next figure shows the parts of a subnet prefix for a 6to4 site, such as you would include in the ndpd.conf file.
The format line in the previous figure contains the following parts.
Part |
Length |
Definition |
---|---|---|
Prefix |
16 bits |
6to4 prefix 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. |
The example in the previous figure has the following values.
Advertisement Part |
Corresponding Value |
---|---|
6to4 prefix |
2002 |
IPv4 address |
8192:56bb, which corresponds to IPv4 address 129.146.87.188 |
Subnet ID |
1 |
/64 |
Length of prefix |
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 form.
prefix:IPv4 address:subnet ID:host ID/64 |
The results of ifconfig –a 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 |
The 6to4–derived address follows inet6 in the output from ifconfig.
Address Part |
Corresponding Value |
---|---|
Prefix |
2002, which is the 6to4 prefix |
IPv4 value |
8192:56bb, which is the IPv4 address, in hexadecimal notation, for the 6to4 pseudo-interface that is configured on the 6to4 router |
subnet ID |
9258, which is the address of the subnet of which this host is a member |
MAC address |
a00:20ff:fea9:4521, which is the link layer address of the host interface that is now configured for 6to4 |