Internet censorship is denial of access to certain websites and is usually controlled by government. There are various levels of denial but in certain countries it is highly restricted to access internet freely. Some widely used restrictions are;
1. IP blocking – Access to certain IP will be blocked
2. DNS filtering – Don’t resolve IP or mislead with erroneous IP.
3. URL/Packet filtering – scan for text in URL or packet and block.
4. Web feed blocking – restricting access to rss feeds, blogs etc.
However, total censorship of information on the Internet is very difficult (or impossible) to achieve due to the underlying distributed technology of the Internet. Pseudonymity and data havens (such as Freenet) allow unconditional free speech, as the technology guarantees that material cannot be removed and the author of any information is impossible to link to a physical identity or organization.
Here is a world-map taken from wikipedia that shows where each country stands as far as the restrictions are concerned.
There are many free anonymous ways to browse and to protect privacy online
Psiphon – Psiphon, believes in a world without borders, where knowledge is power, where people have the right to choose, and ethics, not censorship guides our exercise of freedoms.
Tor – The Onion Router (Tor) enables anonymous communications over internet.
UltraSurf – Protect Internet privacy with anonymous surfing and browsing — hide IP addresses and locations, clean browsing history, cookies & more …
NotMyIP – NotMyIP is a FREE tool that help overcome censorship and browse anonymously by hiding your IP address. It uses only high quality proxies and works with ALL browsers (Internet Explorer, Firefox, Opera, Chrome, etc). No need for manual configuration or additional plug-ins or add-ons.
Hotsopt Shield – Hotspot Shield protects your entire web surfing session; securing your connection at both your home Internet network & Public Internet networks (both wired and wireless).