China Firewall overview

Overview

The Chinese government has implemented a national firewall to block its citizens from accessing specific domains (not only domains hosted with DreamHost but with other web hosting companies as well). While DreamHost does not condone or support their censorship of Internet content, there is nothing that can be directly done to prevent it. However, there are some possible workarounds you could try.

Technical background

The type of web hosting service DreamHost provides is called "virtual hosting" which means that each of the many Apache web server instances running on any server has a specific IP address. Many different domains are hosted under that same IP address. In this configuration, the server uses the domain name portion of the requested URL to determine which site to display.

Simply put, many different domains share the same IP address.

When the Chinese firewall blocks a domain, it blocks the particular IP address that a domain is using. Unfortunately, it also blocks all the other domains that share that same IP address.

My domain is blocked – what can I do about it?

The only current prevention measure you can take is to assign a Unique IP to your domain. By having your own Unique IP address, your domain no longer shares an IP address with other domains. This means if your domain becomes blocked, then it's because they blocked YOUR domain specifically and not because of someone else's domain on the same shared server IP address.

Notes and caveats

• DreamHost can NOT guarantee that by changing the IP address of your domain, it will be unblocked by the Chinese firewall since it’s possible they may block the new Unique IP address as well.
• Please note that the Unique IP you purchase is automatically assigned and may already be blocked.
• When you purchase a Unique IP, the DNS must propagate throughout the Internet which can take several hours.
• When adding, removing, or changing a Unique IP address, the old IP address continues to accept connections for your domain for approximately 5 days. This should allow enough time for the new DNS information to fully propagate throughout the entire Internet. The new Unique IP address should start accepting connections within about 4 hours, but it can take up to 72 hours.
• During the configuration transition, it is not uncommon to see the "Site not found" page when accessing your domain for the first couple of hours. This usually corrects itself on its own.
• If you are not using DreamHost’s Nameservers to handle the DNS for your domain, you must update your nameservers manually with the new IP address for your domain. You can view your DNS information in your panel. Please review the DNS article for further details. Make sure to duplicate your configuration at the company that hosts your nameservers in order for your domain to continue to function.
• There is an additional charge for each Unique IP address you add. 
• If you are entitled to a free Unique IP address, then no charge is applied when you add the first one and no refund is applied when it is removed.
• When removing a Unique IP address from a domain, you receive a prorated refund to your account for its unused portion of time (for that billing cycle).

Google Suite work around

If you're having difficulty using your Google Suite sites such as mail, calendar, and docs, and you're using mail.example.com, calendar.example.com, or docs.example.com, try using instead the alternate addresses indicated below to access your apps with Google:

Mail

http://mail.google.com/a/example

Calendar

http://calendar.google.com/a/example

Docs

http://docs.google.com/a/example

See also