What is the Great Firewall in China and what methods does VPN use to circumvent it? (2026)

For those residing, visiting, or employed in China, the term “Great Firewall of China” (GFW) is probably familiar to you. But what precisely is the GFW? What methods does it use to obstruct foreign websites? Additionally, how can a VPN effectively navigate this sophisticated filtering mechanism? In 2026, grasping these concepts is essential for maintaining security and ensuring stable cross-border connectivity.

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

The GFW represents the most advanced system of national internet filtering and surveillance globally. It is responsible for blocking international websites, censoring sensitive content, and monitoring cross-border traffic behavior. It operates through various layers, including:

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

2. How does the GFW prevent access to websites?

✔ DNS Spoofing

Users are unable to access target sites like Google or YouTube due to falsified DNS responses.

✔ IP Blocking

Requests directed at prohibited IP addresses are quietly disregarded.

✔ SNI Inspection

During the TLS handshake, the SNI field discloses the domain name. If this domain is on the blacklist, the connection is terminated.

✔ Deep Packet Inspection (DPI)

DPI identifies protocol signatures including:

• OpenVPN;
• WireGuard;
• Shadowsocks.

Detection may lead to blocking.

✔ Traffic Behavior Analysis

Even encrypted traffic can be flagged based on:

• Packet size;
• Duration of connections;
• Port usage;
• Traffic bursts.

3. In what ways can a bypass the GFW?

An effective VPN employs several critical technologies:

✔ 1. Obfuscation

This technique disguises encrypted traffic to look like:

• Regular HTTPS browsing;
• Randomized data;
• Traffic from a CDN.

This helps avoid detection.

✔ 2. TLS-like disguising

Certain services integrate their traffic with:

• Legitimate cloud provider data;
• CDN network traffic;
• Standard web surfing.

✔ 3. Multi-protocol fallback

A high-quality VPN accommodates:

• WireGuard with obfuscation;
• OpenVPN (XOR or TLS mode);
• WebSocket + TLS;
• Shadowsocks AEAD;
• TCP/443 fallback.

This strategy helps to avoid long-term blocks.

✔ 4. Automatic server rotation & intelligent routing

This feature ensures:

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

✔ 5. DNS anti-pollution

This includes:

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

4. Why do certain tools frequently fail in China?

This is due to:

• The absence of obfuscation;
• Utilization of standard ports;
• Revealed IP addresses;
• Failure to implement fallback protocols;
• No China-optimized routing;
• Incorrect DNS settings.

5. Criteria for selecting a tool that consistently evades the GFW