Introduction #

A domain being blocked (i.e., rendered inaccessible, typically by the Great Firewall) is not always the result of a report. Restrictions on network access are usually caused by multiple factors, such as government policies, cybersecurity considerations, or technical routing issues. In certain countries and regions, specific websites or services may be blocked to control information flow or for security reasons. Therefore, if you encounter a situation where a domain is inaccessible, it may not necessarily be due to a report. The reasons for a domain being blocked can vary and may include the following scenarios:

Common Scenarios #

1. Content Violations: If a website contains illegal content or breaches local laws and regulations—such as politically sensitive topics, pornography, violence, or gambling—it may be proactively identified and blocked by regulatory authorities, not necessarily requiring a report.
2. User Reports: It is indeed possible for a domain to be blocked due to reports from users or organizations. If someone submits a complaint about a website’s content to the relevant authorities, regulators may review it and decide whether to block it.
3. Keyword Triggers: The Great Firewall (GFW) uses technical methods to scan websites for keywords or links. If content associated with a domain triggers an automated filtering mechanism, it could be blocked even without a report.
4. IP Association: Sometimes the domain itself is not at fault, but if its server’s IP address is flagged as “sensitive” or shared with other blocked sites, it may be collaterally blocked.
5. Proactive Blocking: Certain foreign websites (e.g., Google or parts of Wikipedia) are systematically blocked for policy reasons, unrelated to reports, as part of a broader restriction strategy.
6. Political Reasons: Websites addressing sensitive political or military topics may be blocked.
7. Security Threats: Sites hosting malware, viruses, or posing cybersecurity risks may be blocked to protect users from attacks.
8. Technical Issues: In some cases, network access restrictions may arise from technical problems.

If you find a domain inaccessible and want to determine the exact cause, you can try contacting the relevant internet service provider (ISP) or government agency for more information.

In-Depth Analysis #

The mechanisms triggering domain blocking constitute a multidimensional, composite system, not solely driven by user reports. Below is a detailed analysis from four perspectives: technical, policy, collaborative mechanisms, and empirical data.

I. Technical Perspective: The Proactive Monitoring System of the National Firewall (GFW) #

1. Keyword Filtering System

The GFW analyzes network traffic in real time at export gateways, sniffing and blocking sensitive keywords (e.g., political, terrorism-related, or pornographic content) in unencrypted HTTP data. For instance, when a blocked keyword is detected, the system sends an RST packet to disrupt the TCP connection, causing webpage loading issues.

2. IP Address and Port Blocking

• IP Blocking: By forging routing rules to intercept specific IP ranges, this can lead to collateral blocking of shared servers (e.g., overseas virtual hosting users affected unintentionally).
• Port Blocking: Intermittent blocking of ports like VPN’s 1723 or SSL’s 443 disrupts services periodically (e.g., fluctuations in Google service connectivity in mainland China).

3. DNS Hijacking and Pollution

The GFW manipulates DNS resolution results, redirecting sensitive domains to fake IPs or unrelated pages. For example, during Google’s 2002 blockade, its domain was hijacked and redirected to Baidu.

II. Policy Perspective: Mandatory Enforcement of Cybersecurity Regulations #

Online content must align with national security and public interest standards. Key review focuses include:

• Content Compliance: Illegal information related to politics, terrorism, pornography, or gambling.
• Supply Chain Security: Procurement of critical information infrastructure must pass national security reviews.
• Data Sovereignty: Overseas IPs or servers storing sensitive data may trigger blocking.

III. Collaborative Mechanisms: The Supporting Role of User Reports #

Report Processing Workflow #

User reports submitted via the “Online Reporting Platform” undergo review by a human audit team. If violations are confirmed, the blocking process may be expedited, though it’s not a direct trigger.

Differences in Typical Cases #

• Politically Sensitive Content: System monitoring dominates (e.g., keyword-triggered blocks within seconds).
• Pornography/Gambling: User reports and system monitoring work in tandem, often combined with traffic anomaly analysis (e.g., sudden spikes in nighttime traffic).
• Technical Collateral Damage: Domain resolution errors or IP-associated blocks may lead to misjudgments (e.g., DNS issues during the 2021 Facebook outage).

IV. Data Support: Multidimensional Evaluation System and Empirical Ratios #

According to public cybersecurity reports, the triggers for domain blocking include:

• System Monitoring Accounts for Approximately 70%: This includes keyword filtering, IP behavior analysis, and traffic anomaly detection.
• User Reports Account for Approximately 30%: These primarily supplement hidden violations like pornography or fraud.
• Technical Collateral Blocking: For instance, sealing an IP range affects users of the same service provider (specific ratios undisclosed but notably impactful).

V. Causal Logic Deepening: Composite Judgment Model #

In practice, a tiered approach of “primary intelligent monitoring, supplemented by human reports” is followed:

First Tier: Automated System Screening #

Real-time interception based on the GFW’s keyword database, IP blacklist, and traffic baseline models.

Second Tier: Human Review #

Content audits for user reports or system false positives, judged against Cybersecurity Law provisions.

Third Tier: Collateral Blocking #

Expanded blocking of the same IP range or associated domains of offending servers to enhance enforcement efficiency.

Conclusion #

Domain blocking results from the combined effects of technical monitoring, policy enforcement, and user participation. While user reports serve as a valuable supplementary channel, intelligent system monitoring (e.g., GFW keyword filtering and IP behavior analysis) remains the core triggering mechanism. In the future, as AI-driven content recognition and big data analytics advance, network blocking mechanisms will evolve toward “real-time alerts + intelligent interception + dynamic feedback,” further reducing reliance on manual intervention.