What does it mean when a domain is blocked by the GFW? How can a blocked website be fixed?

　　If your domain resolves normally and can be pinged, but the website won't open (ruling out server downtime), and it hasn't been suspended from resolution by the registry, yet it opens when you use a proxy or VPN, this shows the domain has been blocked by the Great Firewall. Third-party platforms online can check whether a domain is blocked. Today we'll explain: what does "being blocked" mean? How do you fix a blocked website? 【SEO Optimization】

　　1. What does it mean for a domain to be blocked?

　　What we call a domain being "blocked" means, in plain terms, that the domain has been placed on the national firewall's blacklist, or the website's IP has been placed on the GFW (Great Firewall) blacklist. The reason a domain gets blocked may be that the website under it contains illegal information or sensitive content that does not comply with domestic laws and regulations.

　　The GFW most commonly blocks domains and very rarely blocks IPs. The symptoms of being blocked by the GFW are as follows: once it detects that a URL access request initiated from a domestic IP contains a blacklisted domain, some kind of disconnection mechanism is triggered, cutting off that access; at the same time, for the next few minutes, other accesses initiated from that domestic IP to other websites on the IP where the blacklisted domain resides will also be interrupted. After a few minutes, if no access is made to the blacklisted domain, the mechanism will not be triggered.

　　2. How a blocked domain manifests

　　1. The IP the domain resolves to is put on the blacklist

　　In this case, everything returns to normal as soon as you change the IP, but changing the IP only relieves the immediate problem. Once the GFW discovers it again, the domain will very likely be blocked outright, so we still recommend that you proactively remove illegal content from your website.

　　2. The domain is put on the GFW blacklist

　　After ruling out IP/DNS hijacking, this means the domain has been entered into the GFW's database. At this point the website cannot be accessed domestically, but it can be accessed and used in Hong Kong or abroad. Common foreign websites such as google, facebook, youtube, etc., cannot be accessed domestically precisely because they have been blocked.

　　3. DNS hijacking

　　More observant webmasters may notice that sometimes opening a website over China Telecom broadband redirects to another page, while opening it over China Mobile or Tietong works normally — this is very likely DNS hijacking. There are also many criminals who carry out hijacking through third-party DNS, so while ruling out problems with Telecom, Mobile and the like, you should also analyze whether the third-party DNS you use is behaving abnormally.

　　Normally, websites have trustworthy domain name servers on the internet, but to reduce network traffic, domains generally cache the data from external domain name servers so that the next time another machine requests resolution of the domain, service can be provided immediately. Once the domain name server cache of a relevant domain is poisoned, computers within that domain will be directed to the wrong server or server address.

　　3. How to fix a blocked domain

　　1. Resolve the blocked domain to a domestic server and complete ICP filing; once successful, apply for unblocking.

　　2. Bind a new domain on the server and use a domestic forwarding server to redirect the blocked domain to the new domain; by setting up a site-wide 301, transfer the original domain's weight to the new domain.

　　3. Resolve the domain to some large domestic site (such as baidu) — it can only be said that it may get unblocked.

　　4. Switch to a new domain, check the website's information, clean out sensitive content, and make sure the site's content complies with domestic policies and regulations.

　　As for domains that have already been blocked, apart from the remedial measures above, judging from materials from all sides, once a domain is blocked there is basically no solution, especially for websites in gray areas. The only exception is to use domestic hosting after filing the domain, though in that case the website may become inaccessible from abroad.

　　That's the full content of "What Does It Mean When a Domain Is Blocked? How Do You Fix a Blocked Website?" — for the interaction, exchange and learning of fellow webmasters only. SEO Optimization is a process that requires persistence, and we hope everyone can make progress together.