You can do a whois search at arin.net to see the allocation.
172.0.0.0/12 is often confused with the private 172.16.0.0/12 address space, which I would consider a 'scraping the bottom of the barrel' allocation. I also noticed a couple of subnets in that range showing up in the weekly Cidr reports, beginning in July. On 08/23/12 00:29 -0500, Otis L. Surratt, Jr. wrote:
Dan, Can you provide a link to support this? If this is true, I wonder how this will work. Otis -----Original Message----- From: Dan White [mailto:dwh...@olp.net] Sent: Thursday, August 23, 2012 12:24 AM To: nanog@nanog.org Subject: 172.0.0.0/12 has been Allocated 172.0.0.0-172.15.255.255 was allocated on 2012-08-20 to AT&T Internet Services.
-- Dan White