Unassigned IPv4 addresses have nearly run out. In February of this year the IANA assigned the last two available blocks of IPv4 addresses to APNIC (Asia-Pacific Network Information Centre). The recent proliferation of IP enabled mobile devices coupled with the indiscriminate 'sailor on shore leave' assignment of large IP blocks to corporations in the early days of IPv4 has lead to the depletion of available IPv4 addresses. NAT and CIDR definitely provided a significant reprieve, but ultimately only delayed the inevitable.
Simple supply and demand economics would suggest that IPv4 addresses will become a commodity in the near future as supply diminishes while demand is still strong. ISPs and network operators will soon be charging their clients for assignment of IPs from their limited pool of available IP addresses (charging for a 'static' IP address is standard practice for end user ISP accounts, but has not been typical for business clients buying colocation space or managed services - this will change). Moreover a 'grey market' in IPs will likely emerge in the coming months, the Microsoft purchase of Nortel IPs for a reported $7.5 million is one striking example of this trend.
The solution is IPv6. IPv6 uses 128 bit addresses and can support up to 340 undecillion addresses (3.4×1038) compared to IPv4's paltry 4.3 billion addresses. IPv6 also brings a number of improvements from a network plumbing perspective chiefly related to multicasting and security. Despite being an established protocol for over a decade, IPv6 adoption has been very slow. For example, if you are using the recently launched Bell Fibe service at home (and a modern operating system) you're likely already IPv6 ready, but if you’re like the majority of folks and using traditional ADSL or cable Internet and a DOCSIS modem, you're probably stuck with IPv4 for now. At work (unless your IT team is particularly progressive or have too much time on their hands) you are likely on IPv4 at least for Internet bound traffic. You can check to see if you are IPv6 ready using this simple test: http://test-ipv6.com/
So IPv4 is running out and IPv6 adoption is slow. What should you do?
First I would suggest evaluating your company's roadmap to IPv6 adoption. When and how will you transition? What will the impacts be? Can your network support both protocols for a period of time? If no one in your organization has the answers then you probably need put some attention on this issue and possibly get some outside help. A great opportunity to bring some attention to this issue in your organization is participation in IPv6 day on June 8th 2011. You can find out more about how you can participate in this awareness event at the Internet Society website (http://isoc.org/wp/worldipv6day/). Second, if you have plans for significant growth in your web infrastructure in the coming months I would recommend securing some IPv4 addresses of your own by applying for an ASN and Class C IP block assignment from ARIN.
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