Check Website Accessibility in China - Great Firewall Test
Understanding Website Accessibility in China
The Great Firewall of China, formally designated as the Golden Shield Project, employs diverse techniques to restrict access to foreign websites deemed undesirable by the Chinese government.
An official, publicly available list of blocked websites is not maintained by the Chinese authorities. Consequently, determining whether a website is accessible within China can be challenging for those outside the country.
Fortunately, several online tools are available to swiftly assess website accessibility from within China.
Methods Employed by the Great Firewall
Website blocking isn’t a static process; the Great Firewall of China utilizes multiple methods, meaning a site’s availability can fluctuate.
For example, a website featuring prominent coverage of events like Tiananmen Square might experience blocking. However, access could be restored once that content is removed from the homepage.
Other blocking mechanisms include DNS record manipulation. In these cases, the firewall directly interferes with the website’s ability to resolve its address.
Furthermore, connections to certain websites may be terminated by the firewall itself, irrespective of the website’s current content. This indicates a more persistent form of restriction.
- Content-based blocking is dynamic and responsive to current events.
- DNS tampering disrupts the fundamental process of website access.
- Connection resets represent a more severe and potentially long-term block.
Therefore, consistent monitoring of website accessibility is crucial for anyone targeting an audience within mainland China.
The Great Firewall of China
Despite its moniker, the regulations enforced by the Great Firewall are often applied unevenly and with inconsistencies. Website access restrictions can vary significantly depending on the specific geographic region within China. The Great Firewall of China provides a rapid method for verifying your website’s accessibility from multiple locations throughout China.
Website Availability Testing
Simply input the URL of the website you wish to test, and the service will transmit the request to five distinct servers situated within China. Each server will then attempt to access the specified website, reporting either a successful connection or a failure.
This process allows for a quick assessment of your site’s visibility.
Limitations of the Service
While straightforward and efficient, this testing method does have certain limitations. Currently, it only permits testing of a website’s main homepage, and not specific subpages. Attempts to test individual subpages resulted in an error message during testing.
Furthermore, the service merely confirms whether a website responds to a request. It does not detect potential request re-routing by the Great Firewall to an alternative server, which could provide a false positive result.
Therefore, while useful for a preliminary check, it’s important to be aware of these potential inaccuracies.
WebsitePulse
WebsitePulse provides a valuable service by enabling the verification of access to specific subpages. The Great Firewall of China doesn't simply block entire websites; it also filters individual pages based on prohibited terms found within their URLs or content.
Furthermore, WebsitePulse facilitates testing from various regions within China. While both the Great Firewall Of China and WebsitePulse offer testing capabilities from Beijing, they differ in their available locations.
Testing Website Accessibility
By entering a webpage address, users can quickly determine whether it is accessible from within China.
It's important to note that WebsitePulse currently allows for checking only one location in China at a time.
Verification with English Wikipedia
Initial tests indicate that the English Wikipedia appears to be accessible.
Consistent results would be obtained if the same test were conducted using the Great Firewall Of China platform.
Detailed Analysis of Blocking
However, a more in-depth examination reveals that certain sections of the website are subject to blocking.
Specifically, the Wikipedia page dedicated to the Great Firewall itself is currently inaccessible.
Observe that the system displays a message stating “Failure in Receiving Network Data” rather than a straightforward “Blocked” notification.
Important Note: The Great Firewall typically does not provide users with explicit notifications when a website is blocked; instead, blocked requests often manifest as general network errors.
Results obtained from a testing location in Seattle help to clarify the situation – Wikipedia as a whole is not experiencing downtime; access issues are limited to this specific page when accessed from within China.
ViewDNS: Detecting DNS Interference
ViewDNS is a tool designed to identify instances of DNS poisoning. A common method employed by the Great Firewall involves redirecting users attempting to access specific websites to alternative destinations.
For instance, a user located in China attempting to reach Google might instead be directed to Baidu, a China-based search engine. This redirection can falsely indicate successful website loading in other diagnostic tools.
Understanding DNS Manipulation
Another tactic involves altering a website's DNS record, effectively pointing it to a non-existent location. Consequently, the website becomes inaccessible to users.
ViewDNS allows you to input a website address and compare the expected IP address with the IP address returned by DNS servers within China.
The tool also attempts to access the website from various geographical locations, providing information on the success or failure of these connection attempts.
Analyzing Regional IP Address Variations
Observe in the example provided how Facebook’s website resolves to different IP addresses depending on the region. None of these addresses successfully load the website, effectively preventing access.
Interestingly, the server in Inner Mongolia experienced a timeout instead of receiving an incorrect IP address. This raises the question of whether Facebook is being blocked differently in that specific region, or if a genuine network issue is present.
Determining the cause – firewall interference versus a legitimate network problem – can be challenging when dealing with the complexities of the Great Firewall.
- DNS Poisoning: The act of corrupting a DNS server's data.
- DNS Record: An entry that maps a domain name to an IP address.
Circumventing China's Internet Restrictions
If your website is inaccessible within China, you might be seeking methods to restore access. Regrettably, a formal appeals procedure is unavailable. The primary course of action involves eliminating any content or keywords identified as problematic, with the hope of regaining access.
However, a publicly available list of prohibited content does not exist, creating a complex situation. The Great Firewall operates by blocking IP addresses, meaning that multiple websites can be affected if they share an IP with a site that has been flagged.
Fortunately, encrypted internet connections are not subject to blocking by the Great Firewall. Inspecting encrypted data streams is not feasible, and encryption is essential for online security, therefore, its blockage is impractical.
Consequently, foreign VPN services and proxy servers can be effectively utilized to bypass these restrictions. Individuals located in China can utilize a VPN or proxy server to tunnel past the Great Firewall and gain access to the unrestricted internet.
How the Great Firewall Operates
The Great Firewall employs several techniques to control internet access. These include IP address blocking, DNS poisoning, URL filtering, and deep packet inspection.
IP address blocking prevents access from specific IP addresses. DNS poisoning redirects users to incorrect IP addresses. URL filtering blocks access to specific web pages. Deep packet inspection analyzes the content of data packets to identify and block prohibited content.
It’s important to note that the effectiveness of these methods can vary, and the Great Firewall is constantly evolving.
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