How to disable compression for specific user agents in IIS6

compressioniis-6windows-server-2003

I'm seeing some problems with IE6 (pre SP2) that seem to be related to http compression. I'd like to disable http compression just for those users. Any suggestions?

Something along the lines of this might work (but for IIS, not Apache).

Best Answer

ISAPI Rewrite runs on IIS 6.0, so the solution on that page you linked, should work:

Simply add the following lines to the global rules file (httpd.conf in your ISAPI_Rewrite installation directory):

RewriteEngine on

RewriteCond %{HTTP:User-Agent} MSIE\ [56]
RewriteCond %{HTTP:User-Agent} !SV1
RewriteCond %{REQUEST_URI} \.(css|js)$
RewriteHeader Accept-Encoding: .* $1

If you don't want to spend 99 USD for the license (I think it's worth, I used it myself on IIS 6.0), there is an open source project on CodePlex, which works in a similar way.

Related Solutions

Tomcat – HTTP compression in IIS 6.0 causing problems with certain users

Ok, I think we've figured it out...

On the client side, Squid 2.5 and earlier doesn't understand "Transfer-encoding: chunked", so it delivers each chunk as the entire client request. Since it's only 1 chunk of the entire compressed request, it's invalid data and can't be read by the browser. (Not sure if this is an issue with other proxies)

On the server side, IIS always sends chunked encoding for Dynamic Compression (since IIS doesn't cache application responses, it has to compress each response on the fly, hence the chunked encoding).

The only way we can think of to fix this is to completely disable compression for HTTP 1.0 clients and only compress for HTTP 1.1 responses. The drawback is that anyone behind a proxy that sends 1.0 requests won't get compressed data and the site will load 0.5 - 1 second slower for those users.

Changes made in the metabase.xml file:

<IIsCompressionSchemes            Location ="/LM/W3SVC/Filters/Compression/Parameters"
...
HcDoOnDemandCompression="TRUE"
HcNoCompressionForHttp10="TRUE"
...
</IIsCompressionSchemes>

If anyone has a better solution, please let me know!

Getting HTTP Compression (GZip) to work with URL Routing on IIS 6

Make your ASP.NET application gzip its output itself with a method like this one.

Best Answer

Related Solutions

Tomcat – HTTP compression in IIS 6.0 causing problems with certain users

Getting HTTP Compression (GZip) to work with URL Routing on IIS 6

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