When it comes to IPv6 there are a lot of topics that can be discussed. It will change the Internet forever as we know it. IPv4 is the fourth version of protocol using a 32 bit address space whereas IPv6 will be using 128 bits of hexadecimal addressing to allow for drastically more addresses. Currently IPv4 allows roughly 4,294,967,296 possible addresses and with the current allocation practices it limits the number of public address to a few hundred million. In contrast, the 128 bit address space that IPv6 uses can provide roughly 3.4 x 1038 possible addresses.
The sheer size of the IPv6 address allows for the subdividing of the address into a hierarchical routing structure that in turn can reflect the current topology of the Internet. This will provide great flexibility for the addressing and routing in the future where the IPv4 obviously lacks in comparison. It would hard to imagine a world where we do have anymore Internet addresses to go around. This should hopefully solve that problem, at least for a while to come.
When configuring DHCP on Linux to use IPv6 one must be sure that they have everything in order. The two most used means of auto configuration IPS are on the router advertisement and dhcpv6. When you are using the RA a server daemon needs to advertise a network prefix which is typically a /64, gateway and sometimes a DNS server. Then the Client machines can auto configure their IPv6 addresses when they have initialized a bootup based on their current MAC address using EUI64.
When addressing the same situation with dhcpv6, dynamic or static addresses can always be assigned to the current client machines. Unfortunately the gateways cannot be assigned due to the design of the dhcpv6 protocol. If you must use dhcpv6 you have to use RA. You can configure RA to advertise only the gateway leaving the IP and DNS server configuration all up to the dhcpv6, or only the DNS servers. In order to run dhcpd in IPv6 mode you need to add a -6 argument.
The arguments should define the configuration file and lease file. Here is an example of a startup command; /usr/sbin/dhcp -6 –cd/etc/dhcpd6.conf –lf/var/state/dhcpd6.leases eth1. The -6 enables the IPv6 mode and the –cf defines the IPv6 configuration file. Here’s an example of the dhcpd6.conf; # dhcpd6.conf authoritative; option dhcp6.name-servers 2001;db8;1;1;;200; option dhcp6.domain-search ‘internal.1an’;
In conclusion, I hope that after this you understand why IPv6 is such a game changer and why it is so important for our world going forward. Without it our planet would cease to exist and everything would stop. Obviously IPv4 is still around and will be for a few more years, but the days of thinking that IPv4 would last forever or definitely over and it’s time for something new will hopefully last a little longer.
http://technet.microsoft.com/en-us/library/cc780310(v=WS.10).aspx //www.cisco.com/web/about/security/security_services/ciag/documents/v6-v4-threats.pdf http://linux.ardynet.com/ipv6setup.php