HD@THU

Today morning, when I visited my site, I got an error page, saying

ERROR

The requested URL could not be retrieved

The following error was encountered while trying to retrieve the URL: http://www.thuhd.com/
Unable to forward this request at this time.
This request could not be forwarded to the origin server or to any parent caches. The most likely cause for this error is that the cache administrator does not allow this cache to make direct connections to origin servers, and all configured parent caches are currently unreachable.
Your cache administrator is webmaster.

Generated Tue, 01 Dec 2009 01:56:35 GMT by demil1.byetcluster.com (Lusca/LUSCA_HEAD)

So byethost was down. And from this error message, we get these information:
1,Byethost.com uses squid as cache server.
2,Byethost.com uses clusters.
3,Free web hosting is not so reliable.