A leading VOIP provider, Vonage, has filed a complaint with the Federal Communications Commission (FCC) about “an instance of portblocking… by a high-speed Internet provider.” This is not the first time the issue of port blocking and VOIP has been raised. A port is a “logical connection” location used with TCP/IP and UDP protocols. Certain port numbers are assigned, by the IANA, to specific protocols or services. For example, port 80 is reserved for HTTP traffic. When you access a website in your browser you are actually conecting to a web server running on port 80. Port blocking by countries and companies for various reasons is not a new thing: Saudi Arabia blocks access to standard proxy server ports to counter possible circumvention of their national Internet filtering my own ISP, Bell Sympatico, blocks access to port 25 (SMTP) apparently in an effort to combat spam. There are reports that British Telecom blocks access to ports associated with VOIP. And Panama requires ISP’s block access to ports associated with VOIP.
Older articles have reported* that “dozens of countries that ban VoIP services” including “Cuba, Egypt, Israel, South Africa, Kenya, Mexico and Argentina”. There are also additional sources, also somewhat dated, from the ITU, which also list the countries that prohibit certain Internet services. Here is a good summary of ITU country case studies on IP telephony.
* The source information in the Cnet article is incorrect, the actual source for this information is:
Approach to the International Regulatory Issues of IP Telephony
Montana, Shaun P.
Boston University Journal of Science & Technology Law
8 B.U. J. Sci. & Tech. L. (2002)