Internet user, you should know that IPv4 address exhaustion is becoming closer, or let’s use a more appropriate term: imminent!
As you can see from the image on the right (a screenshot taken from the Hurricane Electric web site) the countdown for the estimated date of IPv4 address exhaustion will reach 0 tomorrow! In fact, the last free IPv4 /8 block has been assigned in these days by IANA.
Who is IANA? IANA is the authority that distributes addresses to the regional Internet registries (such as RIPE), for assignment to end users and local Internet registries (such as ISPs). The IPv4 address list has 256 blocks, each block has 16,777,216 /8 addresses, so we have 4.3 billion IPv4 total addresses.
What will happen now?
You may have heard about IPv6, the ‘new’ Internet Protocol, established in 1998 to supplant IPv4. Whereas IPv4 uses 32 bit addresses, IPv6 uses 128 bit addresses, which dramatically increase number of available addresses from 4.3 billion to:
340,282,366,920,938,463,463,374,607,431,768,211,456
But, is the world ready to migrate? I don’t think so.
Someone can say migration has already started. In fact every modern OS has an IPv4/IPv6 dual-stack implementation, but this is not true for network devices, such as most of the routers, switches, etc. Moreover world lack of IPv6 ready services (such as the main one, DNS, we only have a few IPv6 ready DNS) and, most of all, a global TCP/IP network infrastructure that is not IPv6 compliant yet. There are also a lot of security issues. NAT is no more necessary with IPv6, and hiding IP topology will not be a security strategy anymore.
) su IRCNet con IPv6 e DNS AAAA, di quelli superfantasiosi. Ora però mi incuriosiva il fatto di poter sfruttare l’intera sottorete per distribuire indirizzi v6 sui pc di casa. Allora mi sono detto, perché non rispolverare la Fonera e creare una bella sottorete IPv6 dinamica? 
