Donnerstag, 19. Januar 2012

TMG 2010 or ISA or ans Kind of Reverse Proxy and Dynamics CRM 2011 - Client Side Caching Issue caused by Vary: *

TMG 2010 or ISA or ans Kind of Reverse Proxy and Dynamics CRM 2011 - Client Side Caching Issue caused by Vary: *
I read a lot of stuff regarding bad performance an TMG or ISA Server.
And if we have the same issue at customer site at the moment, I like to add an summary of our finding here.


The Vary: * is clearly the problem as Internet Explorer (using IE 9) will not cache or use the local cache for a response with that in the header. This results in the large JS files being sent over and over (sometimes for a single action in the User Interface) and instead of 6KB we see 170KB coming across the wire. And the count if request is also much more. For example when you open an contact which is already cached it should take 3 http request. Including the Very * Issue we need 60-70 http request to open an contact!!


Cache-Control: public
Vary: *

to the response header. This “Vary:  *”  is causing the behavior that some CRM Page elements are not used out of the Internet Explorer Cache.

Due to new informationswe know now that this can be fixed / is cause by a special ISA / TMG Configuration. If you configure the ISA / TMG in an other way it will work properly. Will update this article with further details once they are available for publishing.

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