E164.org is a public ENUM root for use with VoIP systems who support ENUM 164 number resolution including Asterisk and SER. 

E164.org differentiates itself from other ENUM services in a number of ways. 

E164.org verifies telephone numbers and is available for use by the public at large. 

E164.org does not force service providers to establish layer 2 peering, this enables businesses and consumers alike to switch calls over the Internet or any network path they locally choose; enabling them to establish flexible dial plans that can leverage least cost routing across the Internet, alternate service providers such as Nufone or even an existing telephone line using Zapata hardware from Digium 

E164.org also allows users who have a regular telephone line, to also hook themselves up to the Internet without intervention from their regular telephone service provider while still using their "plain old telephone" number instead of a web, IP or some other address. 

In addition to VoIP addressing; E164.org also supports Email and Instant Messaging NAPTR types allowing a phone number to be used as a single point of reference for communicating with a person using a variety of methods. 

Both "real" numbers can be added after verification and "free" blocks of 100 numbers are available. 

E164.org is a donation based system and is free for the public at large to use. 

For example, here we use the unix dig command to lookup up information stored in the DNS system rooted in e164.org for the phone number 1-800-555-5555, i.e. a random US toll free number. We ask for any records stored for this number. 




$ dig +short 5.5.5.5.5.5.5.0.0.8.1.e164.org any 
100 10 "u" "E2U+SIP" "!^\\+1800(.*)$!sip:1800\\1@216.234.116.184!" . 
100 10 "u" "E2U+IAX2" "!^\\+1800(.*)$!iax2:guest@216.234.116.184/1800\\1!" . 




What we get back describes to ways to reach that number using different transport schemes, using SIP and one using IAX2. 
That information was actually stored in the NAPTR records associated with the domain 5.5.5.5.5.5.5.0.0.8.1.e164.org; so we would probably actually have done this to get this info: 




$ dig +short 5.5.5.5.5.5.5.0.0.8.1.e164.org NAPTR 
100 10 "u" "E2U+SIP" "!^\\+1800(.*)$!sip:1800\\1@216.234.116.184!" . 
100 10 "u" "E2U+IAX2" "!^\\+1800(.*)$!iax2:guest@216.234.116.184/1800\\1!" .