What exactly is China's Great Firewall, and what methods does VPN employ to circumvent it? (2026)

Should you reside, visit, or be employed in China, you're probably familiar with the term “Great Firewall of China” (GFW). But what is the GFW in detail? How does it manage to prevent access to foreign websites? Furthermore, how can a VPN effectively navigate around such a sophisticated filtering mechanism? In 2026, grasping this knowledge is essential to maintain security and ensure reliable cross-border connectivity.

1. What Constitutes the Great Firewall of China (GFW)?

The GFW is recognized as the leading national internet filtering and surveillance framework globally. It obstructs foreign websites, screens sensitive material, and analyzes cross-border traffic trends. Its functionality is built upon several layers:

• DNS spoofing;
• IP blocking;
• SNI inspection;
• Deep Packet Inspection (DPI);
• Traffic behavior analysis;
• Port filtering.

2. In What Manner Does the GFW Prevent Access to Websites?

✔ DNS Spoofing

Fabricated DNS responses stop users from accessing websites like Google or YouTube.

✔ IP Blocking

Requests directed to blacklisted IP addresses are discreetly denied.

✔ SNI Inspection

During the TLS handshake, the SNI field discloses the domain name. If the domain is prohibited, the connection is terminated.

✔ Deep Packet Inspection (DPI)

DPI identifies protocol signatures that include:

• OpenVPN;
• WireGuard;
• Shadowsocks.

Detection may result in blocking.

✔ Traffic Behavior Analysis

Encrypted traffic can still be flagged based on:

• Packet sizes;
• Connection length;
• Port utilization;
• Traffic surges.

3. How Can a bypass the GFW?

A robust VPN leverages various essential technologies:

✔ 1. Obfuscation

This technique disguises encrypted traffic to appear as:

• Typical HTTPS browsing;
• Randomized information;
• CDN activity.

This approach mitigates detection risks.

✔ 2. TLS-like Camouflage

Certain services integrate traffic to mimic:

• Legitimate cloud service traffic;
• CDN network operations;
• Standard web surfing.

✔ 3. Multi-protocol Fallback

A high-quality VPN offers support for:

• WireGuard with obfuscation;
• OpenVPN (in XOR or TLS modes);
• WebSocket combined with TLS;
• Shadowsocks AEAD;
• TCP/443 fallback.

This reduces the chances of prolonged blocking.

✔ 4. Automatic Server Rotation & Intelligent Routing

This provides:

• Lower risk of blocking;
• Enhanced latency and speed;
• Multiple alternative routes.

✔ 5. Anti-pollution DNS

This encompasses:

• Secure DNS (DoH/DoT);
• SmartDNS;
• Custom anti-pollution DNS routing.

4. Reasons Certain Tools Fail in China