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No-No on DLLs (ZipEnable compression on IIS 6/ASP.NET)

Quick post, but worthy of your attention if you use the native IIS 6 compression on Windows Server 2003, ASP.NET (and if you use ZipEnable to manage IIS 6 native compression...).

ASP.NET does have a mapped DLL that outputs content from the application server (simple version of story for the process geeks out there).  However, we have noticed some ZipEnable and IIS 6 native compression users adding “.dll“ to the list of dynamic files types to compress...  This causes, well, Web server crashes when you are running ASP.NET and is a mistake to avoid.  Just add “.aspx“ to the list of dynamics to compress, and you should be set to compress ASP.NET output.

As a general note, if you have a filter or DLL mapped (like with WebSphere, WebLogic app servers) on the Web server, IIS 6 compression will not work anyways.  httpZip will get that job done.

As a far removed but important side note, if you are serving an .exe file, you probably don't want to compress that either on IIS 6 with the native compression (think of your Web server being hit by one of those DOD MOABs or bunker busters -- not a pretty sight).

Tanks,
Port80

 

 

posted on Wednesday, February 15, 2006 1:36 PM

Feedback

# re: No-No on DLLs (ZipEnable compression on IIS 6/ASP.NET)

Can you elaborate a bit more on the filter or DLL mappped (like WebSphere)
3/8/2006 2:38 PM | Bootch

# re: No-No on DLLs (ZipEnable compression on IIS 6/ASP.NET)

WebLogic and WebSphere have DLL connectors into IIS that make the app servers compatible with the MS Web server. In our experience, native compression on IIS 6 does not play well with DLLs or filters that modify requests, like these mentioned above or a filter like ISAPI Rewrite.

In those cases, httpZip as a filter itself can be adjusted to load order, which can affect the sequencing of events and data within IIS, and that make all the difference between a crash (compatibility-wise) and a compressed Web server response.

Of course, there is more special sauce than that to make an IIS compression filter compatible with systems like WebLogic and WebSphere, but we don't always give away the full recipe (or we would be out of business but fast :) ).

Cheers,
Chris @ Port80
3/9/2006 10:40 AM | Chris @ Port80

# Mr

Will ZipEnable and standard IIS6 compression not work then with Mod-Rewrite?
http://www.micronovae.com/ModRewrite/ModRewrite.html
1/23/2008 2:37 AM | Mark Langille

# re: No-No on DLLs (ZipEnable compression on IIS 6/ASP.NET)

The better choice would be httpZip (www.httpzip.com), which has been designed to work with URL rewriters. With ZipEnable, you are just managing the IIS 6 compression engine, so if there is a conflict with one of your unique URL writing rules and compression, your only choice there is to disable compression. We suggest testing your URL writing rules with ZipEnable first. If there is conflict, try httpZip, which is designed for this case. Also, please let Port80 Support know if you need any help (www.port80software.com/support) along the way!
1/23/2008 10:21 AM | Chris @ Port80

# re: No-No on DLLs (ZipEnable compression on IIS 6/ASP.NET)

thanks nice text
4/7/2008 7:54 AM | software

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