Europe has tapped out its supply of Internet addresses in its assigned range, but some tech prospectors believe they've found some IPv4 gold—a full block of 16,777,216 addresses that isn't used to connect to the Internet. But the British government agency that owns the block of addresses (referred to in IP networking as a /8 block) has no intentions of giving it up, even though almost none of the addresses will ever be publicly accessible. That has inspired an electronic petition campaign on a House of Commons website to convince British lawmakers to auction off the address block.

John Graham-Cumming, a programmer for CloudFlare and technology book author, pointed out the address block (from 51.0.0.0 to 51.255.255.255) in a recent blog post, noting that it was apparently unused. Based on a Network World article from May, he estimated the block coud be worth as much as $1.5 billion on the open market, given that it's essentially the last unused block of its size.

The Department of Works and Pensions, which was assigned the block by RIPE NCC (Réseaux IP Européens Network Coordination Centre), acknowledged its ownership of the address block in a response to a Freedom of Information request made by James Marten on behalf of the public watchdog site Whatdotheyknow.com last December. The addresses—or at least about 80 percent of them—are in use, according to a letter from DWP spokesman Phil Tomlinson on behalf of the department's IT group, but none are intended to be accessed from the public Internet. The remainder are being used as the basis for a proposed Public Services Network—a private government intranet.

That would make the addresses ripe, so to speak, for conversion to a private network, and for the addresses to be freed up for other use. However, Tomlinson wrote, "DWP have no plans to release any of the address space for use on the public Internet." The reason, he claimed, was that readdressing the existing systems already configured with addresses from the block would be too expensive. "DWP are aware that the worldwide IPv4 address space is almost exhausted, but knows that in the short to medium term there are mechanisms available to ISPs that will allow continued expansion of the Internet, and believes that in the long-term a transition to IPv6 will resolve address exhaustion," he wrote; besides, the address pool would only last a few months.