Why is my website blocked in China?

Someone in Shanghai tells you your website won’t open. You sell software, or legal advice, or apartments. You’ve never published a word about politics, so why would China block you?

Politics is only part of the answer. This guide sets out the documented causes, what the evidence shows and where it stops.

It’s part of our guide to putting your website in China.

Why do websites get blocked in China?

Six causes are documented, and at least three of them have nothing to do with what you published. Here’s the short version. For totals, see how many sites are blocked.

Cause	What triggers it	Aimed at your site?	Main evidence
Content	Topics banned by Chinese rules	Yes	Rule text 5
Type of service	File sharing, proxies, AI tools, news	Apparently, by category	GFWeb, 2024 1
Shared IP	A blocked site on your address	No	Chai et al., 2019 3
Broad name rule	A blocked string inside your domain	No	GFWatch, 2021 2
Provincial firewall	A separate regional list	Unclear	Wu et al., 2025 4
Your host	No ICP on a mainland server	Yes, but not by the state	GFWeb, 2024 1

Does anyone tell you why?

Not that we could find. We found no official list, no published criteria and no stated reason for any individual block. The blocklists described here were reconstructed by outside researchers running tests.

The authors of GFWeb, a 2024 study, write that no official report on the firewall’s design has ever been published.¹

China Briefing wrote in 2017 that there were “no formal criteria” for a ban, and no formal appeal process.⁸

In October 2011, the US Trade Representative asked China who decides, by what criteria, and whether a blocked company can appeal or go to court.⁹ We found no published answer.

The law gives a framework, not a reason. Article 15 of the Measures on internet information services lists banned content for service providers.⁵

The 2016 Cybersecurity Law, in Article 50, says authorities shall notify the relevant bodies to block banned information coming from abroad.⁶

That law was amended with effect from January 1, 2026, and its articles were renumbered.⁷

How these texts apply to your foreign site is a question for a local adviser.

Cause 1: content the rules prohibit

Banned content is the one cause with a published list behind it, and that list is broad. Article 15 lists nine categories, which we’ve grouped here:⁵

• Opposing constitutional principles, or harming national security, state secrets or national unity
• Damaging national honor and interests
• Inciting ethnic hatred, undermining religious policy, or promoting cults and superstition
• Spreading rumors or disturbing social order
• Obscenity, pornography, gambling, violence, murder, terror or incitement to crime
• Insulting or defaming others
• Anything else banned by law or regulation

The last item is a catch-all, so the list can’t work as a safe checklist. See sensitive content on a Chinese website.

Commercial content isn’t automatically safe either.

Cause 2: the kind of service you run

Some sites seem to be blocked for what they are. GFWeb classified 79,500 censored base domains and found that five categories made up 60%.¹

Those five are file sharing and storage, adult content, malicious sites, information technology and business.¹

News, proxy tools, parked domains, blogs and gambling complete its top ten.¹

Categories also shift with events. In 2023, GFWeb saw AI services such as chat.openai.com, deepai.org and huggingface.co become censored, along with domains containing “GPT”.¹

The authors link that wave to AI regulation and call it a sign of economic protectionism, favoring domestic companies.¹ That’s their reading, not an official reason.

If your site hosts uploads, forums or comments, you also carry content you didn’t write. That last point is our inference, not a measured finding.

Being small doesn’t protect you. In GFWatch’s 2020 data, only 1.3% of 138,700 censored base domains ranked in the top 100,000 sites.²

The authors conclude the list is likely curated by both automated tools and manual effort.²

Cause 3: a neighbor on your IP address

This is real, but its current scale is unknown. A 2019 study of the top million sites found 39,787 blocked by IP, about 84.5% of the censored sites it counted.³

The authors argue many were collateral damage. The sampled sites looked innocent, while sites sharing their servers carried sensitive content.³

CDNs aren’t exempt. The same study found 47 blocked Cloudflare addresses, shared by at least 85 sites.³ The US government raised the problem back in 2011.⁹

Using a big cloud is no shield. GFWeb found that most censored domains sit on Western cloud providers.¹

1. Google92,069
2. Cloudflare77,298
3. CyberNet Servers76,354
4. Amazon (AMAZON-02)65,540

GFWeb (2024). Note: these are hosted volumes, not a risk rate, and they do not add up across filters.

Those counts show where censored domains live. They don’t show that any provider raises your risk. Our guide to shared IP blocks has the detail.

Cause 4: a blocking rule that catches your name

This happened at scale, but it has become much less likely. Filters match patterns, and a loose pattern catches unrelated names. A rule for torproject.org also hit mentorproject.org.¹

GFWatch tracked the DNS filter from April to December 2020. It found 311,000 censored domains, of which 41,000 were caught only because they contained a blocked string.²

The authors were also puzzled by cs.colorado.edu, a university department domain blocked along with everything under it, while colorado.edu wasn’t.²

GFWeb reported in 2024 that this problem is largely fixed, though a few broad rules remain on the HTTP filter.¹ If your domain contains a well-known blocked name, it’s still worth a look.

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Cause 5: a provincial firewall

Your site can be blocked in one province and open elsewhere. Researchers documented a separate firewall in Henan, blocking traffic leaving the province.⁴

They tracked it from November 2023 to March 2025, with a gap from March to October 2024.⁴

Measure (Wu et al., 2025) 4	Henan firewall	National firewall
Domains blocked, cumulative	4,196,532	741,542
Business share, categorized domains in the top million only	26.9%	15.3%
*.gov domains blocked	1,002	83

Only 479,247 domains appeared on both lists, so being clear nationally didn’t mean being clear in Henan.⁴

This is the clearest evidence here of blocking with no visible link to politics. Henan blocked texas.gov and seattle.gov, which the national firewall didn’t.⁴

On some dates in 2024 it blocked all 5,334 tested .com.au domains, which the authors call possible overblocking.⁴

Limits apply. In Henan, the study measured a single ISP, China Unicom, from machines in Zhengzhou. It tested six other provinces and municipalities and found nothing, with limited coverage.⁴ We don’t know what has happened since.

Cause 6: your host, not the censor

If your site is on a mainland server, a block may come from the provider. GFWeb saw Aliyun and QCloud redirect HTTP requests for 7.8 million and 6.8 million domains to ICP warning pages.¹

The authors say plainly that this isn’t the Great Firewall or state censorship. Even example.com triggered QCloud’s redirect.¹ So we read those counts as what the probes triggered, not as how many sites those hosts carry.

Alibaba Cloud says a domain pointing to its mainland servers without an Alibaba Cloud filing is blocked by its monitoring system, and invites you to file.¹⁶

This one has a clear fix. See ICP filing vs ICP license.

What looks like a block but isn’t

Several ordinary failures produce the same symptom. Rule these out before you look for a deeper cause.

• A short, general disruption. On August 20, 2025, all connections on port 443 were reset for about 74 minutes, whatever the site. The cause is unconfirmed.¹¹
• Local interference. GFWeb attributes most gaps with other platforms to localized interference, not the firewall.¹
• An ISP’s fraud warning. Chinese ISPs have redirected users to an “Anti-Fraud” page. GFWeb saw triggers last only briefly, found no pattern, and notes baidu.com was one.¹
• A blocked dependency. Chinafy, which sells a fix, said in 2022 that most sites that seem inaccessible had technical problems.¹⁷ See which Google services fail.
• A single-network result. GreatFire warns that different networks can reach the internet differently from its probes.¹⁸

How to work out which cause applies

Match what you see to the likely cause. No public tool we found proves the cause, and a test on a URL doesn’t always separate an IP block from a name block.

What you see	Most likely	Next move
An ICP warning page	Your mainland host	Check your filing
One region or network fails	Local or provincial issue	Retest on several networks
An “Anti-Fraud” warning page	ISP redirect	Retest later
Failures everywhere for minutes, then normal	Short disruption	Retest later
Page opens, then stalls or breaks	Dependency or speed	Audit what the page loads
Repeated failures across mainland probes	A real block	Follow the steps below

If it looks like a real block:

1. Test properly. Use several tools and networks, as explained in how to check your site from China.
2. Date it. Find when it started, and what changed then: a new server, section or embed.
3. Review your content. Include old posts, comments, uploads and anything a third party can publish. If you bought the domain, check what it hosted before. GFWeb’s list held many domains that no longer exist or host nothing, so we infer a block can outlast the content.¹
4. Ask your host. Find out if your IP is shared, and whether others on it report the same problem.
5. Get advice if China matters. A local adviser can assess your content and exposure.

1. Block confirmed?

   No: see slowness and dependencies.

2. Yes: hosted on the mainland?

   Yes: check the filing.

3. No: only one network?

   Yes: local or provincial problem. No: review the content, then ask the host.

Will changing host or getting an ICP fix it?

It depends on the cause, and nothing guarantees a result. We found no documented appeal route, and China Briefing said in 2017 that no formal one existed.⁸

If the cause is	A new host or IP	An ICP
Shared IP	May help, no guarantee	Not needed for this
Name or domain	Unlikely to help (our inference)	Unproven
Your content	Won’t address it	Unproven
Provincial firewall	Unknown	Unknown
Host enforcement	Not the point	Yes, if you stay on that host

Name filters work on the domain, which is why we don’t expect a move to help there.

On addresses, DreamHost warns that a new IP may already be blocked.¹³ Bluehost’s page describes a dedicated IP but says its accounts don’t offer one.¹²

AppInChina presents an ICP filing as the fix for a blocked site.¹⁴ We found no evidence that a filing lifts a block on a site hosted abroad.

China Briefing lists mainland servers and a Chinese business entity among the ICP requirements,¹⁹ and Alibaba Cloud says filing applies only to mainland servers.¹⁶

The mainland route adds its own checks. Cloudflare says its partner JD Cloud must review the content of every domain on its network.¹⁵ Weigh this in your hosting options.

The bottom line

A block doesn’t prove you did anything wrong. Shared addresses, broad rules and regional lists all catch sites that were never the target.

Confirm the block, rule out the ordinary failures, then work through the causes. Expect a likely answer, not a certain one.

How Index in China can help

We don’t unblock websites, and we don’t offer workarounds. We translate sites into Simplified Chinese with a human reviewer and work on getting them indexed by Chinese search engines.

On a first call, we look at your site and what getting indexed would take. If your case needs a local adviser, we’ll tell you.

See what we do, or book a 30-minute call.

Book a 30-minute call

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