We have a website which targets customers in China, both expat and local Chinese. We have an ICP license which allows us to host in a datacenter inside China. Internet in China is actually as fast as anywhere else (faster than most places actually), so long as the content is served-up within the boundaries of the Great-Firewall. Anything that crosses the wall is horribly slow.

The problem is that most expats have some sort of VPN installed so that they can access all the blocked stuff. What this means is that when they access our site, the traffic first has to go out of China through the firewall to their VPN, and then back in. The performance is terrible, worse than if we were just hosting outside of China directly (which we used to do before the ICP was issued).

So I want to use a global CDN to mirror the site automatically, but I only want to deliver the content via the CDN if the user's request IP address is outside of China. Inside China I would like the content to be served by our own server.

I also want to be careful with the domain names. We currently use www.xxx.com and www.xxx.cn for language selection purposes, as these perform well in SEO on Google (which the expats use), and Baidu (which the locals use). If possible I would like to avoid having one domain on the outside, and the other on the inside since not all expats use a VPN, and some Chinese speakers also use VPNs. Also some of our legitimate customers in both languages are from outside of China.

I also don't want to resort to using something like www2.xxx.com/cn for the outside connection if at all possible, since I have worries about duplicate content and canonical URLs ruining our SEO (unless you know of a quick fix for that).

CDNs I'm considering are: Google PageSpeed, CloudFlare, Amazon CloudFront. None of which have datacenters inside China. I have complete control of the .com DNS zone records, but the .cn zones are under the control of the domain issuing body in China. I'm not sure at this time if they would allow even a CNAME to point to an IP outside of China (although I don't see why not). They no longer allow outside registrars like they used to.