Introduction #

In internet operations, domain blocking is a frequent and vexing issue, with numerous websites restricted due to policy or content violations. When a website or domain is blocked by government authorities for breaching regulations or policies, it often involves deeper technical and administrative layers. Network censorship measures go beyond simply preventing access to a specific IP address—they also encompass control over domain resolution and other tactics.

Website administrators often attempt to use a 301 redirect (permanent redirect) to reroute traffic to an unblocked new domain in hopes of restoring access. However, many find that even after setting up a 301 redirect, users still cannot access the site, and the new domain may quickly get blocked as well. Why does this happen? The primary reason is that a 301 redirect is essentially an HTTP response code sent by the web server to the browser, instructing it to visit a specified new URL. However, this does not alter the underlying network censorship measures that block the domain.

I. What Is the Nature of Domain Blocking? #

To understand why a 301 redirect fails, we first need to grasp the mechanics of domain blocking. The GFW (Great Firewall) is a sophisticated censorship system that employs various technical methods to block specific websites, including IP blocking, DNS pollution, and keyword filtering. When a domain is blocked, users attempting to access it may encounter messages like “Unable to connect” or “Webpage cannot be opened.”

• IP Blocking: The GFW may directly block the server IP address associated with the domain.
• DNS Pollution: User DNS requests are tampered with, returning incorrect IP addresses and preventing resolution to the correct server.
• Content Censorship: If the website’s content triggers sensitive keywords, it may also face dynamic blocking.

A blocked domain is essentially flagged by the GFW as “inaccessible,” and this designation often comes with multiple technical restrictions.

II. How Does a 301 Redirect Work? #

A 301 redirect is an HTTP status code indicating a “permanent redirect.” When a user or search engine visits a URL, the server returns a 301 status code, informing the client (browser or crawler) that the requested resource has permanently moved to a new URL.

• User Experience: The browser automatically redirects to the new address, typically unnoticed by the user.
• SEO Impact: Search engines partially transfer the old domain’s authority to the new domain.

Under normal circumstances, a 301 redirect is a standard tool for website migrations or domain changes. However, when a domain is blocked, the situation becomes far more complex.

III. Why Doesn’t a 301 Redirect Work When a Domain Is Blocked? #

Here are the core reasons why a simple 301 redirect fails to resolve the issue:

1. GFW Blocking Occurs Before the Request Reaches the Server #

The GFW’s interception mechanisms typically operate at the network or transport layer, while a 301 redirect is an application-layer (HTTP protocol) operation. In other words, when a user tries to access a blocked domain, the GFW may have already blocked the request via DNS pollution or IP blocking before it even reaches the server—let alone triggers a 301 redirect. For example:

• If DNS is polluted, the user resolves an incorrect IP and never connects to your server.
• If the server IP is blocked, data packets cannot reach the destination even if resolution is correct.
• In such cases, the 301 redirect instruction never gets a chance to execute.

2. New Domains Are Easily Linked and Identified #

Even if you manage to guide traffic to a new domain through alternative means (e.g., manually notifying users), the GFW can identify the connection between the old and new domains in several ways, such as:

• Same Server IP: If the old and new domains point to the same IP address, the GFW may quickly blacklist the new domain.
• Redirect Signal Exposure: A 301 redirect explicitly reveals the relationship between the old and new domains in the HTTP response header, allowing the GFW to monitor and swiftly block the new domain.
• Content Similarity: If the new domain’s content closely resembles the old domain’s, it may trigger the GFW’s automated detection mechanisms.

3. DNS Cache and Client-Side Issues #

Even if a 301 redirect is configured on the server, clients (user devices) may remain stuck on the blocked old domain due to DNS caching or local network conditions. Particularly in cases of DNS pollution, users may not even perceive the redirect.

4. GFW’s Dynamic Blocking Capabilities #

The GFW is not a static blocking system; it has dynamic learning and adaptation abilities. If it detects a blocked domain attempting to “bypass” restrictions via a 301 redirect, it may proactively track the redirect target and quickly block the new domain. This “pursuit” mechanism significantly undermines the effectiveness of 301 redirects.

IV. Common Operational Missteps #

When dealing with domain blocking, many administrators fall into the following pitfalls, rendering their 301 redirect efforts futile:

• Ignoring IP Replacement: Changing only the domain without updating the server IP allows the GFW to continue blocking based on the IP.
• Unencrypted Redirects: Using HTTP instead of HTTPS for 301 redirects makes the redirect information easily interceptable by the GFW.
• Obvious Domain Connections: If the new domain closely resembles the old one in registration details, server setup, or content, it increases the risk of linked blocking.
• Expecting Instant Results: Assuming users can access the site immediately after setting up a 301 redirect overlooks DNS propagation delays and the GFW’s response time.

V. How to Address Domain Blocking? #

While a 301 redirect has limited effectiveness when a domain is blocked, the following strategies may help mitigate the issue:

• Change IP and Use a CDN: Deploy the website to a new server IP and utilize a CDN (Content Delivery Network) to distribute traffic, reducing the risk of direct blocking.
• Conceal Redirect Relationships: Avoid direct 301 redirects; instead, use front-end scripts or temporarily notify users to manually visit the new domain, minimizing GFW association detection.
• Multi-Domain Backup: Maintain multiple backup domains and rotate them periodically to prevent a single block from paralyzing the entire site.
• HTTPS Encryption: Use HTTPS throughout to ensure redirects and content transmission are not easily intercepted or analyzed.
• Decentralized Deployment: Consider distributed technologies (e.g., IPFS) or proxy services (e.g., Cloudflare) to diffuse blocking pressure.

VI. Case Study #

Take an overseas news website as an example: after its domain A was blocked, the administrator set up a 301 redirect to a new domain B. However, within a week, B was also blocked. Analysis revealed that A and B shared the same server IP, and the redirect process was unencrypted, enabling the GFW to quickly identify and block B. Ultimately, the administrator switched to a new server IP, adopted CDN acceleration, and notified users via social media to visit the new domain, temporarily restoring normal access.

Conclusion #

The fundamental reason a 301 redirect fails after domain blocking lies in the GFW’s blocking mechanisms, which take precedence over HTTP-layer redirect operations, coupled with its dynamic tracking capabilities that make it hard for new domains to evade bans long-term. To tackle this issue, administrators must address IP replacement, encrypted transmission, and concealing domain associations, rather than relying solely on 301 redirects. In the ever-changing internet landscape, maintaining technical flexibility and user communication channels is the key to sustainably managing domain blocking.