Wake up call for our friends in the Regional Internet Registries. Nortel, the Canadian telecommunications equipment manufacturer that filed for bankruptcy protection in 2009, has succeeded in making its legacy IPv4 address block an asset that can be sold to generate money for its creditors. The March 23 edition of the Dow Jones Daily Bankruptcy Report has reported that Nortel's block of 666,624 IPv4's was sold for $7.5 million – a price of $11.25 per IP address. The buyer of the addresses was Microsoft. More information is in its filing in a Delware bankruptcy court. Now the interesting question becomes, does the price of IPv4s go up or down from here? As the realities of dual stack sink in, I'm betting…up.