There are a number of techniques to get past Internet filtering. If your aim is simply to reach pages or services on the Internet that are blocked from your location, and you are not concerned whether other people can detect and monitor your circumvention, these techniques may be all you need:
There are a number of different ways you can reach the content on a Web page by going through a third-party web site rather than directly to the source web site.
Many search engines keep copies of Web pages they have previously indexed, called cached pages. When searching for a Web site, look for a small link labeled "cached" next to your search results. Since you are retrieving a copy of the blocked page from the search engine's servers, and not from the blocked Web site itself, you may be able to access the blocked content. However, some countries have targeted caching services for blocking, as well.
RSS aggregators are Web sites that allow you to subscribe to and read RSS feeds, which are streams of news or other information put out by sites you have chosen. (RSS stands for "Really Simple Syndication"; for more on how to use it, see http://rssexplained.blogspot.com/.) An RSS aggregator connects to Web sites, downloads the feeds that you have selected, and displays them. Since it is the aggregator connecting to the Web sites, and not you, you may be able to access sites that would otherwise be blocked. This technique works only for Web sites that publish RSS feeds of their content, of course, and therefore is most useful for blogs and news sites. There are a lot of free, online RSS aggregators available. Some of the most popular ones include Google Reader (http://reader.google.com) and Bloglines (http://www.bloglines.com).
Below is an example of Google Reader displaying the news:
There are many language translation services available on the Internet, often provided by search engines. If you access a Web site through a translation service, the translation service is accessing the blocked site, not you. This allows you to read the blocked content translated into a number of different languages.
You can use the translation service to bypass blocking, even if you don't actually need to translate the text. You do this by choosing translation from a language that does not appear on the original Web site back to the original language. For example, to use a translation service to view an English-language Web site, choose translation from Chinese to English. The translation service translates only the Chinese sections (there are none), and leaves the English sections (which is the whole Web page) untranslated.
The example below illustrates the three steps necessary to view a page in Babelfish. First, enter the URL of the Web site you wish to visit:
Next, choose the language you wish to read the Web site in. In this example, we tell Babelfish to translate from Korean to English. Since there is no Korean text, the page will remain untranslated.
When you have chosen the language, click "Translate" and the page displays.
Low-bandwidth filters are Web services designed to make browsing the Web easier in places where connection speeds are slow. They remove or reduce images, remove advertisements, and otherwise compress the Web site to make it use less data, so it downloads faster. But, as with translation and aggregation services, you can also use low-bandwidth filters to bypass simple Web site blocking by fetching Web sites from their servers rather than from your computer. One useful low-bandwidth filter is at http://loband.org/.
Simply speaking, a DNS server translates a human-friendly Web address such as google.com into the IP address that identifies the specific server with that page on the Internet, such as 18.104.22.168. This service is most often provided by DNS servers maintained by your Internet Service Provider (ISP). Simple DNS blocking is implemented by giving an incorrect or invalid response to a DNS request.
You can potentially bypass this type of blocking with these techniques:
One of the most common ways to censor a Web site is to block access to its domain name, for example, "news.bbc.co.uk". However, sites are often accessible at other domain names, such as "newsrss.bbc.co.uk". If one domain name is blocked, try to see if the content is available at another domain.
An extension of this technique is to bypass the Domain Name Servers of your local ISP, using third-party servers to reach domains that may be blocked by the ISP's servers. There are a number of free, internationally available DNS services that you can try. OpenDNS (https://www.opendns.com/) provides one such service and also maintains guides on how to change the DNS server that your computer uses (https://www.opendns.com/smb/start/computer/). There is also an updated list of available DNS servers from around the world at http://www.dnsserverlist.org/.
E-mail and Web-mail services can be used to share documents with groups of friends or colleagues, and even to browse the Web.
Similar to low-bandwidth filters, there are services intended for people with slow or unreliable Internet connections that let you request a Web page via e-mail. The service sends a reply e-mail that includes the requested Web page either in the body of the message or as an attachment. These services can be quite cumbersome to use, since they require you to send a separate request for one or more Web pages, and then wait for the reply, but, in certain situations, they can be very effective at reaching blocked Web pages, especially if you use them from a secure Web mail service.
One such service is web2mail.com. To use it, send an e-mail message to email@example.com with the Web address (URL) of the Web page you want in the Subject line. You can also perform simple Web searches by typing searches into the Subject line. For example you can search for censorship circumvention tools by typing "search censorship circumvention tools" in the subject of an e-mail message and sending it to firstname.lastname@example.org.
You can find more information and support on this topic on the ACCMAIL mailing list. To subscribe, send an e-mail with "SUBSCRIBE ACCMAIL" in the body to email@example.com.
If you are trying to share documents online, but want to control who can see them, you can keep them in a private space where they are visible only to those with the correct password. A simple way to share documents among a small group of friends or colleagues is to use a single Web mail account with an online e-mail provider, such as Gmail (https://mail.google.com/), and to share the user name and password with those who need to access the documents. Since most Web mail providers are free, it is easy to switch to a new account at intervals, making it harder for anyone outside the group to keep track of what you are doing. A list of free online e-mail providers is located at www.emailaddresses.com/email_web.htm.
These simple techniques are quick and easy to use; you can try them with minimal effort. Many of them will work at least some of the time in many situations. However, they are also easy to detect and block. Since they do not encrypt or otherwise hide your communications, they are also vulnerable to keyword-based blocking and monitoring.