⚠️ Disclaimer This tool is for technical research and network diagnostics only. Results are for reference only and do not represent any political stance. Please comply with local laws and regulations.
Domain Blocking Check
Check if a domain is blocked in mainland China (GFW), including DNS resolution, HTTP/HTTPS connectivity tests.
Common Use Cases
- Website administrators check if their domain is accessible from mainland China
- Operations teams troubleshoot server connectivity issues
- Foreign trade businesses verify domestic access to overseas services
- Network engineers analyze DNS resolution and network path status
About Domain Blocking
Domain blocking means a domain cannot be accessed in mainland China. Common causes include DNS pollution, IP blocking, and SNI inspection.
Common Blocking Methods
- DNS Pollution: Returns incorrect DNS results：
- IP Blocking: Blocks the target server's IP address：
- SNI Inspection: Filters based on SNI in TLS handshake：
- Keyword Filtering: Inspects HTTP request keywords：
Frequently Asked Questions
How accurate are the check results?
Results are for reference only. Checks are performed from mainland China servers simulating domestic user access. However, different regions and ISPs may have varying network conditions. Actual access depends on local testing.
What solutions exist for blocked domains?
Common solutions include: changing server IP (for IP blocking), using HTTPS instead of HTTP (bypasses some SNI inspection), migrating to filed domestic servers, or using CDN services to distribute traffic.
What's the difference between 'blocked' and 'banned'?
Blocked typically refers to GFW filtering affecting all domestic users. Banned may mean the domain was shut down by hosting providers for lacking filing, or by authorities for violations. They have different causes and solutions.
Network Blocking Technologies
Network blocking primarily uses three techniques: DNS pollution (tampering DNS responses with wrong IPs), IP blocking (blocking specific IPs at router level), and deep packet inspection (analyzing packet content for filtering).
HTTPS encryption protects transmitted content from analysis, but the SNI field in TLS handshake may still expose the target domain. Technologies like ECH (Encrypted Client Hello) are being developed to address this privacy concern.