Can a shared IP get your site blocked in China?

Your content is harmless, yet the site won’t open in China. Shared hosting is the first suspect, and your host’s help page will probably say so.

The evidence behind that claim is real, but mostly old and less tidy than those pages suggest.

This guide is part of our work on putting your website in China. It covers one question: what your IP neighbors can do to you.

Can a shared IP really get your site blocked?

Yes. A block on an IP address hits every site on that address, whatever each one publishes. Bluehost and DreamHost both tell their customers this.⁵⁶

The idea is old. Harvard researchers found 308 blocked sites on one registrar’s parking server.¹⁰ Ben Edelman concluded in 2003 that filtering by IP address “is bound to lead to overblocking”.⁹

The best measurement we found is Chai et al. They tested the Alexa top 1 million list from April 2019, using one server in China and one in the US.¹

What blocked the site	Sites	Share of 47,069 censored sites
IP, alone or with other methods	39,787	84.5%
IP and nothing else	22,859	48.6%
IP, DNS and SNI together	16,666	35.4%
SNI and nothing else	70	0.1%

1. IP, alone or with other methods84.5%
2. IP and nothing else48.6%
3. IP, DNS and SNI together35.4%
4. SNI and nothing else0.1%

Shares are our arithmetic from the paper’s Figure 4.¹ SNI is the site name your browser sends when it opens a secure connection.

How likely is it today?

Nobody can say. We found no study after 2019 that counts how many sites are blocked by IP, so any percentage you read for today is a guess. The studies we have don’t agree either.

Study	Finding	Limit
CacheBrowser, 2015	No CDN edge server filtered by IP, DNS interference dominant 3	CDNs only
Chai et al., 2019	47 blocked Cloudflare addresses shared by at least 85 sites 1	Few addresses, one vantage point
Hoang et al., 2020	Nearly 90% of addresses tied to sensitive sites host one sensitive domain, so “little to no collateral damage” 2	Modeled from a global list, not tested in China
GFWeb, 2024	Overblocking “largely mitigated” 4	Covers name rules, not IP blocks
Tang et al., 2024	718 domains suspected blocked over TCP/IP anomalies, with hosting IPs the suggested cause 22	Suspected, on a search-built test list, so no rate

GFWeb is easy to misread. It describes filters on names being tightened, and it gives no IP blocking figure.⁴ It doesn’t show that IP blocking has eased.

Tang et al. is the newest evidence we found. They tested from Beijing and Shanghai between November 2023 and March 2024.²² Most domains with TCP/IP anomalies weren’t on the firewall’s name lists, and the authors suggest their hosting IPs were blocked instead.²² So the practice looks current, even though nobody has sized it.

Don’t turn the 2019 count into your odds. The 22,859 IP-only sites are about 2.3% of the list by our arithmetic,¹ and a top-sites list isn’t a sample of small business sites.

Exposure is wide, though, because sharing is normal. In Hoang’s 2019 data, only 17.5% of domains had an IPv4 address to themselves, and over 60% of sites sat with at least ten others.²

How to tell an IP block from a name block

Look at where the connection dies. An IP block stops it before your site’s name matters. A name filter lets the connection start, then cuts it.

Chai et al. marked an address as filtered when ports 80 and 443 showed nothing open from China, yet were open from the US.¹

GFWeb describes the other case: the filter spots a domain in the Host or SNI field and injects reset packets.⁴

What you see from China	Likely cause	Would a new IP help?
TCP fails on 443 and 80, works from abroad	IP block, or your own firewall	Possibly
TCP connects, then resets at TLS or HTTP	Filter on your name 4	No
DNS returns an address that isn’t yours	DNS poisoning 4	No
Fails on one node or in one province	Local interference 414	Test more first
Fails from everywhere, including abroad	Your server 13	No

Local failures are real. Researchers documented a Henan firewall with a cumulative list of about 4.2 million domains, more than five times the national one, measured through one provider there.¹⁴

Our guide to whether your site is blocked or just slow covers the wider diagnosis.

How to check your own IP

Run this before you pay for anything. Some tools cap guest use, so plan your checks.¹⁷

1. Find your IP. Run a DNS lookup on your domain. If the address belongs to a CDN, go to our CDN guide, since these steps assume your own host.
2. TCPing ports 443 and 80 from China. BOCE lists TCPing with nodes by carrier, so cover Telecom, Unicom and Mobile.¹⁷ ITDog offers the same kind of test.¹²
3. Compare with a control outside China. A failure on both sides points to your server.¹³
4. Space your tests out. Interference can linger after a trigger: Chai et al. saw 60 seconds, and earlier work reported 90. During that window, forged replies can distort a result.¹
5. List your neighbors. A reverse IP lookup shows domains on an address.¹⁶ Expect a partial list, since these tools return a subset.¹¹
6. Test two or three neighbors. If they open from China, your address is probably fine.
7. Point a spare, neutral domain at the same IP. If it fails too, suspect the address. If it passes, suspect your name.
8. Check your own firewall. A security plugin or host rule that rejects Chinese traffic would look exactly like an IP block.

Our guide to testing whether your site is accessible in China covers the URL tools, and why a VPN skews the result.

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Does a dedicated IP fix it?

Only when the address is the problem. Hosts sell this as the remedy, and the evidence for it is thin.

Bluehost’s blog says a dedicated IP “can significantly improve” access, with no data behind it.⁷ DreamHost is more careful: it “may provide a workaround”, and its addresses “may already be blocked”.⁶

The one success story we found dates from 2008. Jonathan Nicol’s client became reachable within an hour of buying a static IP, though the cause was his inference.⁸

Chai’s data shows the limit. Those 22,859 IP-only sites are the group a new address might free. The other 24,210 censored sites also faced DNS or SNI blocking, or only those.¹

A new address may not escape either. One participant on Discourse Meta suggested a block could cover a whole range, though nobody confirmed it.¹⁸

If your tests point at the address, proceed in this order:

• Check availability. Bluehost’s help page says a dedicated IP isn’t currently offered on its accounts.⁵
• Test first. Put the spare domain on the new address and repeat steps 2 to 4 before moving your main site.
• Plan the switch. DreamHost says a new address takes 4 to 72 hours, and the old one keeps answering for about 5 days.⁶
• Retest afterward. Run the checks again from several networks, then again a few days later.

If your domain itself is filtered, don’t try to engineer around it. Read why websites get blocked in China, and take any legal question to a local adviser.

Which setups carry the risk?

All of them carry some, and they differ in how much you can see. Your address’s past matters as much as its present.

Setup	Who shares your IP	Can you see them?	What to watch
Shared hosting	Other customers	Partly, by reverse lookup 11	A neighbor’s block
Dedicated IP on shared hosting	Nobody	Yes	May already be blocked 6
VPS or dedicated server	Usually nobody	Yes	Unknown history of the address
Global CDN	Often many unrelated sites	No, lookups are partial 11	See our CDN guide
Mainland CDN or hosting	Depends on the provider	Ask the provider	Needs an ICP, as Cloudflare’s China Network does 20

Scale is what separates a CDN from shared hosting. Some addresses at major providers serve hundreds of thousands to millions of sites.²

We found no source showing that free CDN plans are more exposed than paid ones.

For the filters themselves, see what the Great Firewall means for your website.

The bottom line

A shared IP can get your site blocked, and the research suggests it has happened at scale. A 2024 study suggests IP blocking continues, but how often it hits innocent sites is unknown, because the last count we found dates from 2019.

So test before you buy. A dedicated IP solves an address problem, and it does nothing for a name problem.

How Index in China can help

We can’t lift a block or change your IP’s history, and we’ll tell you if your case needs a local adviser.

Our work is the next layer: we localize your site into Simplified Chinese, with a person reviewing every page, then index it on Chinese search engines. Book a 30-minute call.

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