Cary Sherman, the head of the Recording Industry Association of America, wrote in a guest column for CNET that SOPA could be used to force Internet providers to block by "Internet Protocol [IP] address" and deny "access to only the illegal part of the site." The RIAA, along with the Motion Picture Association of America and the U.S. Chamber of Commerce, strongly supports the legislation.
[...]
An aide to the House Judiciary committee -- chaired by Rep. Lamar Smith (R-Tex.), SOPA's principal sponsor -- did not dispute that IP address blocking and deep packet inspection could be required. It would be up to a judge to determine the nature of the court order that would be needed to block the site, the aide told CNET this afternoon.
They are definitely looking to block by IP, not just DNS.