The IANA, who's website, www.iana.org, displays the slogan, "Dedicated to preserving the central coordinating functions of the global Internet for the public good.", is the entity which keeps track of all sorts of numbers (and other things) associated with the Internet.

This includes:

• IP Port Numbers Assignments
• Whois information for all of the Country Code Domains
• and a host of other things.. see http://www.iana.org/numbers.htm