Why Internet Explorer 7 cannot(IE7) visit some web sites which IE 6 can access with no problem.
Just read a article from MS guy and got a idea why I cannot use IE7 to visit some web sites while IE 6 got no problem on them:
A quick recap:
- On Windows XP SP2, IE7 will send the following User-Agent header: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1)
- On Windows 2003 Server, IE7 will send the following User-Agent header: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.2)
- On Windows Vista, IE7 will send the following User-Agent header: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0)
Over the last eighteen months, most sites that had previously blocked the new version of Internet Explorer have been updated, and we're happy to report that the vast majority of Internet sites are now accessible using IE7.
There are a few remaining sites which fail to recognize IE7 because they are performing exact string matches to look for specific IE version strings. Those checks will need to be removed or updated to accommodate IE7. The Best Practice document linked from here can be help:
http://msdn.microsoft.com/workshop/author/dhtml/overview/aboutuseragent.asp
http://msdn.microsoft.com/workshop/author/dhtml/overview/browserdetection.asp
To enable you to workaround any remaining sites that block access to Internet Explorer 7, we developed the User Agent String Utility. The utility comes in the form of a small executable that opens an IE7 instance that sends the IE6 user agent string. It also provides a mechanism for you to report problem web sites to Microsoft so that we can follow up with the affected site owners. Please download the tool and give it a try.