5/23/22, 2:51 AM Internet Filtering in Burma in 2005: A Country Study | OpenNet Initiative We carefully analyze the data obtained from testing to document the nature of filtered content, to explore the technical capabilities of the target state, and to determine areas that require in-depth study during internal testing. In particular, ONI examines the response received over HTTP when attempting to access filtered content. As discussed, when content is filtered, users often receive a "block page" - a Web page with text indicating that the requested content cannot be accessed.70 In other cases, filtering can be less obvious or transparent, appearing to be network errors, redirections, or lengthy timeouts rather than deliberate blocking. We analyze HTTP headers - text sent from the Web server to the browser - to derive information about both the server and the requested page. This information is generally hidden from the end user. However, these headers indicate whether content was successfully accessed or was inaccessible. If an error occurs, the HTTP protocol returns codes that indicate the type of error in the header. Thus, by analyzing the headers captured during testing, we can distinguish between errors caused by Internet filtering and more mundane, unintentional network connection errors. We classify results in one of four categories: URL is accessible both through the local connection and the remote computer (not filtered); URL is accessible through the local connection but inaccessible through the remote computer, which returned a different HTTP response code (possibly filtered); URL is accessible through the local connection but inaccessible through the remote computer due to a network connection error (possibly filtered, but not definitive); or URL is accessible through the local connection but inaccessible through the remote computer; the remote computer returns a block page (filtered). If a URL is inaccessible through both the local connection and the remote computer, we consider it "dead" and remove it from the results. The ONI team analyzes blocked, unblocked, and uncertain URLs both at an aggregate level (to estimate the overall level of filtering) and at a category level (to indicate what types of content the state seeks to control). We publish country studies that provide background on a state's political and legal system, lists of tested sites, and analysis of results to reveal and analyze what information a state blocks and how it does so. We note, however, that our results and analysis capture a "snapshot" of a state's filtering system for a specific point or period of time; governments can and do alter the content they block dynamically. This is particularly true for Burma, where the implementation of the Fortinet filtering software has reportedly increased the level of blocking of Internet content beyond that which was carried out using the DansGuardian open source filtering system. C. Methods Specific to Burma To evaluate Burma's filtering, we tested two lists (the global list and a high-impact list designed for Burma) from an access point on the ISP Bagan Cybertech within the state. This involved direct in-state testing on a broadband connection by a trusted volunteer.71These tests used the software application developed by ONI to examine filtering. D. Topics Tested ONI tested topics to which the Burmese government has demonstrated sensitivity. These include dissident and political opposition sites, pages on Burma's human rights record, sites about the indigenous Karen people, commentary and news pages, sites on circumventing filtering, and non-governmental organizations. 4. RESULTS AND ANALYSIS A. Summary Burma filters certain content categories heavily, including political opposition sites, human rights pages, email service providers, and pornography. This blocking is also broad, filtering at least one site in more than half the categories ONI tests on its global list. The approach of broad-based, but relatively inconsistent, filtering tends to have a particularly chilling effect on expression, as citizens are kept wondering about whether they will be able to break through the filter and whether or not they are being watched. Thus, in addition to strong legal and economic controls over Internet access and content, Burma implements a filtering regime that imposes significant limits on the material the state's citizens can access. ONI's research suggests that Burma has moved from the DansGuardian filtering software to Fortinet's Fortiguard product since the time of our testing. Reports from in-country sources indicate that Burma's blocking has become more restrictive since this change. Thus, our results here likely underestimate the level of filtering experienced by Burmese Internet users at present. B. Global List ResultsONI's testing of its global list in Burma found significant blocking in several categories of Web sites, and at least some filtering in many categories. Web-based e-mail service providers, which provide the most common means of on-line communication in states with low rates of Internet penetration, were https://opennet.net/studies/burma 6/15