Where is ASP.NET 3.5 on IIS ?

Most people on installing .NET 3.5 on the server "expect" an entry for  v3.5 under the ASP.NET version Tab in IIS manager. And not finding that entry start panicking. If you have been one of those read on. The more tech savvy folks try to run aspnet_regiis -i from the v3.5 framework folder... but even that is missing :)

That brings us to the question

What exactly is ASP.NET 3.5 ?

Take a look at the v3.5 framework folder you will not find most of the files needed for ASP.NET to run like aspnet_isapi.dll / aspnet_filter.dll / aspnet_regiis.exe / aspnet_regsql.exe...

The reason being .NET 3.5 is not a stand alone framework like v2.0 or v1.1 . It is just an extension of the 2.0 framework. The extension provides developers with new language features like Anonymous Types, Extension Methods, Lambda Expressions and of course LINQ .... and AJAX is now integrated ... also you have a few new ASP.NET controls <asp:ListView>, <asp:LinqDataSource>, <asp:DataPager>

Will I get ASP.NET version 3.5 under the ASP.NET tab in IIS 6.0 ?

Nope. Because as far as IIS is concerned nothing has changed. The aspnet_isapi.dll from the version 2.0 folder will still handle the requests and there is no new ISAPI dll specific to version 3.5. So you don't have to change any Script Mappings in IIS ...just leave the web application pointing to v2.0 under the ASP.NET Tab. And this brings us to the next question

What exactly is the extension ?

For that if you have Visual Studio 2008 go ahead and create a Website targeting the .NET 3.5 framework. Then go to the Property Pages of the Website and select References. You will find an entry like this

And those four assembly references provide the new features of v3.5.  Here is a 10,000 ft view of the functionality implemented in these assemblies

System.Core - Provides namespaces like System.Linq, System.IO

System.Data.DataSetExtensions - LINQ to DataSet

System.Web.Extensions - AJAX

System.Xml.Linq - New XML API.. supports LINQ to XML

Do I have to configure anything manually ?

No. When you install the .NET 3.5 redistributable on the server it installs these assemblies in the GAC. And any website that refers to these assemblies can fetch them from the GAC so you do not have to configure anything manually. All you need to do is publish the content to a web application that is marked with ASP.NET v2.0

And now you should be thinking

The new language features should require a new compiler. How exactly is the new compiler used ?

The answer is your web.config file. When you create an ASP.NET 3.5 website in Visual Studio 2008 an entry is made in the web.config something like

 <system.codedom>
  <compilers>
    <compiler language="c#;cs;csharp" extension=".cs" warningLevel="4"
              type="Microsoft.CSharp.CSharpCodeProvider, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
      <providerOption name="CompilerVersion" value="v3.5"/>
      <providerOption name="WarnAsError" value="false"/>
    </compiler>

The new features do require a new compiler to be used and the web.config tells .NET that the v3.5 compiler has to be used.

What about IIS 7.0 ?

IIS 7.0 is no different. 

[UPDATE 2012] Where is ASP.NET 4.5 …wait Where is .NET 4.5 ?

Comments

• Anonymous
  March 20, 2008
  PingBack from http://www.stonecode.com/where-is-aspnet-35-on-iis/

• Anonymous
  March 20, 2008
  Most people on installing .NET 3.5 on the server "expect" an entry for v3.5 under the ASP.NET version

• Anonymous
  March 20, 2008
  Thank you for this - it has solved this problem for me - I had already gone down the blind alley with aspnet_regiis. It is much appreciated, especially with the detail of the reasons why this happens. Thanks again.

• Anonymous
  March 21, 2008
  Wonderful article and great explanation. Thanks Vijayshinva Karnure

• Anonymous
  March 25, 2008
  Very good article indeed. I have to admit it is irritating not being able to set the version in IIS.  Maybe/hopefully as I begin using the new updates I will start to understand better then reasoning Microsoft had for doing this.  Right now the only reason I can think of is making the upgrade a smaller install.

• Anonymous
  March 31, 2008
  Simple and very good explanation

• Anonymous
  April 08, 2008
  Ref:http://blogs.msdn.com/vijaysk/archive/2008/03/20/running-asp-net-3-5-on-iis.aspxMostpeopleon...

• Anonymous
  April 10, 2008
  Very good article. I was also one of those looking for a way to "register" ASP.NET 3.5 in IIS.

• Anonymous
  April 15, 2008
  If I am using MSBuildToolsPath set to 3.5 is their anyway to find the path to tools I need (aspnet_regiis) from within msbuild?

• Anonymous
  April 17, 2008
  Thanks for laying out all of the answers in one article!

• Anonymous
  April 22, 2008
  Most people on installing .NET 3.5 on the server &quot;expect&quot; an entry for v3.5 under the ASP.NET

• Anonymous
  April 25, 2008
  Thank you for this info, it was very helpful. Clear consice and accurate.

• Anonymous
  May 07, 2008
  ASP.NET Version when you  installing .NET 3.5 ?

• Anonymous
  May 10, 2008
  thanks..this article was very helpful

• Anonymous
  May 12, 2008
  Thanks a lot... Saved me a lot of unnecessary work

• Anonymous
  May 13, 2008
  A related issue -- my computer does not have an ASPNET account. How do I create it? I have just now installed v3.5 of .NET framework on Windows 2003 Server. Thanks.

• Anonymous
  May 15, 2008
  A really good article to explain something actually quite fundamental.  A lot of developers are not aware of the basic concept that 3.5 is not a standalone framework. Thank you.

• Anonymous
  May 23, 2008
  Great article.  Saved me some time!

• Anonymous
  May 23, 2008
  Exactly what I was looking for. Thank you!!!

• Anonymous
  May 26, 2008
  Thanks for such a nice article

• Anonymous
  June 02, 2008
  Very helpful!!  Like you started your article - I was one of those confused by the whole thing.  Not any more!

• Anonymous
  June 25, 2008
  Thanks, a very helpful article!

• Anonymous
  July 14, 2008
  Thank you for that clarification.

• Anonymous
  July 17, 2008
  Great! thanks for this extremely helpful information

• Anonymous
  August 05, 2008
  yes, useful.i had iis installed after .ne t 3.5 and i wished asp.net  3.5 extension in iis dropdownlist. but it is clear now. regards, sangam http://www.dotnetspidor.blogspot.com

• Anonymous
  August 07, 2008
  Really a good Article!!!!!!!!!!!!!!!!!!1

• Anonymous
  August 28, 2008
  Thank you for clarifying how 3.5 is working in this article. I just installed 2008 and converted the 1st projects. I was confused when I saw 2.0 references in IIS ....  Your article really helped me.

• Anonymous
  September 04, 2008
  The comment has been removed

• Anonymous
  September 16, 2008
  Boy do I feel silly  :)   This was great info, thanks!

• Anonymous
  September 27, 2008
  Thanks Buddy! Very helpful.

• Anonymous
  October 05, 2008
  I re-installed version 3.5 twice... I thought there is a problem... thanks for this article... now I can smile :)

• Anonymous
  October 05, 2008
  I was also one of those looking for a way to "register" ASP.NET 3.5 in IIS. I share my view with Federico Caldas (his post dated 10 Apr 2008).

• Anonymous
  October 21, 2008
  Excellent I was Looking for the same thing. Thanks a lot for such a good explination.

• Anonymous
  October 22, 2008
  Excellent article! Exactly the information I was looking for. Thanks  Danke!

• Anonymous
  October 24, 2008
  Brilliant. Excellent and very useful article. Thanks a lot for sharing your knowledge.

• Anonymous
  October 28, 2008
  This is a very nice article. Thank you very much.

• Anonymous
  October 29, 2008
  I don't know how many times I get asked this same question daily. Thank you for writing the article so clearly and simply. I will certainly offer your URL as part of my answer in the future.

• Anonymous
  November 01, 2008
  Thanxs a lot! Jus to be clear this is the same for IIS 5.0, 5.1, 6.0 and 7.0 ? From your explanations its seems to be that it is

• Anonymous
  November 10, 2008
  Very helpful and very clear explanation. Great

• Anonymous
  November 18, 2008
  Thanks, you saved me from pulling ALL of my hair out.

• Anonymous
  November 19, 2008
  Very helpful and informative article.

• Anonymous
  November 23, 2008
  I have created one project on Visual studio 2005.  I craeted virtual directory and it worked fine. I was able to access it. Now I have installed Visual studio 2008. I have upgraded my project to 2008. I also created virtual directory.              This time it is giving an error when I am trying to browse my project from I.E. The error is failed to access iis metabase. Can you please help me regarding this?

• Anonymous
  November 29, 2008
  Thanks! I just installed VS2008 and was hella confused about "registering" 3.5

• Anonymous
  December 03, 2008
  Kalo arthro. Kerdizeis ena xryso papari .NET 3.5

• Anonymous
  December 18, 2008
  Simple, clean, and direct explanation.  Excellent article. Much appreciated.

• Anonymous
  December 19, 2008
  Excellent Article. I was confused about .net 3.5. Thanks a lot

• Anonymous
  December 29, 2008
  Hats Off !!!!!! Thanks a Bunch !

• Anonymous
  January 11, 2009
  Thanks! Of course, MS could maybe make this a little more obvious?

• Anonymous
  January 13, 2009
  excelent post!!! really helpful

• Anonymous
  January 13, 2009
  Great info and to the point. Bravo!

• Anonymous
  January 21, 2009
  Excellent Article. Answer to many questions. Thanks

• Anonymous
  January 21, 2009
  Thanks for the very Informative article

• Anonymous
  January 29, 2009
  good info and nice presentation..thx

• Anonymous
  January 30, 2009
  Most people on installing .NET 3.5 on the server &quot;expect&quot; an entry for&#160; v3.5 under the

• Anonymous
  February 03, 2009
  The comment has been removed

• Anonymous
  February 05, 2009
  Excellent Article...solved my confusion regarding  3.5 and IIS.

• Anonymous
  February 05, 2009
  Excellent Article...resolved my confusion regarding  3.5 and IIS.

• Anonymous
  February 25, 2009
  Thank!  This article was very helpful.

• Anonymous
  March 12, 2009
  thanks ... very useful ..............

• Anonymous
  March 21, 2009
  Well explained.... simple and neat

• Anonymous
  April 01, 2009
  Thanks, was looking for 3.5 in the tab.  

• Anonymous
  April 13, 2009
  thanks buddy it really helps us to know new things for 3.5

• Anonymous
  April 21, 2009
  The comment has been removed

• Anonymous
  April 21, 2009
  Extremely helpful and well written (with nice illustrations)

• Anonymous
  May 04, 2009
  Thanks for the article...I was looking for the entry, this really saved me a lot of time.

• Anonymous
  May 05, 2009
  Excellent... simple, brief and lets you know what you need to know..

• Anonymous
  May 08, 2009
  The comment has been removed

• Anonymous
  May 18, 2009
  Thanks for this article, but I have still one question. Does this mean that it also still uses the machine.config from the .net framework 2.0?

• Anonymous
  May 19, 2009
  The comment has been removed

• Anonymous
  May 21, 2009
  Very good article. Thank you very much.

• Anonymous
  June 10, 2009
  Thanks for the info - helped a lot to clarify this 3.5 install process, and it's end results.

• Anonymous
  June 14, 2009
  Thanks for this . it is very clear.

• Anonymous
  June 16, 2009
  Thanks for the information, very useful!!!

• Anonymous
  July 07, 2009
  Thanks a lot for the Info. Good Atricle

• Anonymous
  July 09, 2009
  Great article. It explains very clearly.

• Anonymous
  July 17, 2009
  Excellent information.. I have been looking for this info for 2 days and finally got my website to work...

• Anonymous
  July 21, 2009
  Thanks! Simple yet very informative.. :)

• Anonymous
  July 29, 2009
  Superb Explanation !!! Thanks a lot !

• Anonymous
  July 31, 2009
  Very good explaination but I am having a problem here. I recently converted a 1.1 application to 3.5 and everything works fine on local machine. But when its moved to server, i am getting error saying "script manager is not known element". Please help. I have System.Web.Extensions included in my config.

• Anonymous
  July 31, 2009
  Finally I got it resolved. I enabled scripts on the permission tab. And then app worked fine. But I appreciate your article. Its solid.

• Anonymous
  August 08, 2009
  Couldn't have said it any better and simpler Thanks a lot

• Anonymous
  August 13, 2009
  This article was clearly written and very useful.  Thank You

• Anonymous
  August 21, 2009
  Really a nice article keep up the things!!!!

• Anonymous
  August 27, 2009
  I hate to be the guy who isn't posting a "thank you" but I think your presentation is misleading. There is no such thing as ASP.NET 3.5. Microsoft marketing actually deserves most of the blame. ASP.NET has only proceeded to version 2.0. The .NET Framework is versioned separately and has had a 3.0 and 3.5 release. So it isn't really correct to say that ".NET 3.5 isn't a stand-alone framework" in this context because the .NET Framework version doesn't bear any direct relationship to the ASP.NET version number. Just ran across this while looking for something else. :)

• Anonymous
  August 27, 2009
  This blog post saved me a lot of time. Thanks!

• Anonymous
  September 06, 2009
  Thanks & Saved my time as well.

• Anonymous
  September 07, 2009
  Thanks! This article answered all my ASP.NET 3.5 confusions in one place. ;-)

• Anonymous
  September 18, 2009
  Recently we have migrated our code frm 1.1 to 3.5 and i was searching for 3.5 option under asp.net version but i cudn't get it and i have been searching for this since a long time and finally i got this nice explanation here. Thanks for the useful information...this has answered all my questions.

• Anonymous
  September 29, 2009
  hi, i from argentina, MUCHAS GRACIAS :D thank you!!

• Anonymous
  October 03, 2009
  Thanks a lot.... Very nice article...

• Anonymous
  October 09, 2009
  This is great. I was starting to sweat when I did not see the 3.5 version under IIS. Harsha

• Anonymous
  October 20, 2009
  I like many other was puzzeled, not anymore... Thank you so much for the explanation.

• Anonymous
  October 31, 2009
  thanks very much, it was very helpful article

• Anonymous
  November 07, 2009
  How can you tell 3.5 SP1 is installed 3.5.1 on the versions?

• Anonymous
  November 10, 2009
  Really good and helpful. I was running like like a headless chicken to fix (!?!) this problem.

• Anonymous
  November 12, 2009
  Thanks very much for your help! But I have another problem... I installed ASP.Net and the .Net Framework 3.5, and now I'm trying to get a duck to eat cotton candy... can you please help me?

• Anonymous
  November 27, 2009
  After successful install of .net fw 3.5 on windows 2003 server, I went straight into ASP.NET tab and found 3.5 missing in the dropdown list! got no clue even after going through readme etc... and finally stumbled upon this article. Simple and to the point explanation. Bravo! Excellent.

• Anonymous
  November 30, 2009
  Thank you very much for this article. You have explined in very much details and in a very simple language.

• Anonymous
  January 26, 2010
  Good Article. It saved my time

• Anonymous
  January 31, 2010
  Thank you very much...... This is  great...

• Anonymous
  February 04, 2010
  very good article about asp.net framework for iss

• Anonymous
  February 04, 2010
  Excellent Article, exactly the same information for which i was looking for.. Solved lots of confusion going in mind.... Thanks .. Keep it up

• Anonymous
  February 07, 2010
  Thanks a lot! I knew situation and was not expecting 3.5 on IIS but I didn't know why it was ;) Really simple, elegant and complete article. Thanks again!..

• Anonymous
  February 11, 2010
  Great article!  Thanks a lot for the details...  I wondered for a while why 3.5 option is not in the IIS manager

• Anonymous
  March 06, 2010
  i have created one wrapper class to a smart card api, it works fine when i use source code and press f5, but not after creating virtual directory. i am using IIS 6.0 with on Win XP thanks in advance.

• Anonymous
  March 07, 2010
  Thanks a lot.  This time from Spain. I spent over 2 hours trying to find the way to "attach" framework 3.5 to IIS just to find out it was allready done.

• Anonymous
  March 08, 2010
  tengo mi aplicacion hecha en asp.net 3.5 sobre iis 5.1, el servidor iis 5.1 funciona, pero no corre mi aplicacion web; me sale un mensaje: error al compilar v 3.5. ALQUIEN ME PUEDE ORIENTAR

• Anonymous
  March 30, 2010
  Is Microsoft insane?!  Why do they make installs like this so difficult and why don't they just say on the page where you download 3.5?  

• Anonymous
  April 05, 2010
  Great.....Very usuful onformation

• Anonymous
  April 13, 2010
  Grate artical ........................................... very very very helpful.

• Anonymous
  April 15, 2010
  Thank You. found my answers here cheers

• Anonymous
  May 02, 2010
  thanks for content. Old project i use vs2005 and ajax control toolkit 2.0 after i install vs2008 and change ajax2.0 to ajax3.0 and i deploy project to framwork3.5. can i crate deploy web site in iis and run it?

• Anonymous
  May 27, 2010
  Simple and easy language, too the point, solved problem for me.

• Anonymous
  June 09, 2010
  Hi everyone here... You wont find ASP.NET 3.5 on IIS probably because ASP.NET 3.5 uses the same ASP.NET 2.0 engine.

• Anonymous
  June 21, 2010
  Thank you, now I can stop searching about registrering .Net 3.5 in IIS! Can do ths with 2.

• Anonymous
  July 15, 2010
  Thanks for this, was looking for they .net 3.5 is IIS tab

• Anonymous
  October 06, 2010
  Thank you for enlighting on v3.5 and "ASP.Net Version" in IIS. It cleared my adoubt deploying my vs2008 app with v2.x as "ASP.Net Version".

• Anonymous
  November 19, 2010
  Hi Vijay, Very good explanation with good use of pictures. You have cleared all my doubts.

• Anonymous
  April 21, 2011
  Great Article. Very helpful to understand where I was confused. Thank you very much for sharing this !

• Anonymous
  July 27, 2011
  Very very good article... Thanks for your suppor

• Anonymous
  August 29, 2011
  Still useful, and relevant, three years on, thanks :)

• Anonymous
  October 11, 2011
  Thank you so much. You explanation clear out my doubt.

• Anonymous
  September 23, 2012
  Great Article!! thanks!!!! simple, clear, consice and accurate!! i was confused for months about this issue... thanks once again .... keep up the great work :-)

• Anonymous
  June 12, 2013
  Excellent Article.I was wondering why 3.5 was not listed under ASP.NET tab in IIS.

• Anonymous
  October 15, 2014
  Thank you for letting us all know what Microsoft assumes you know, as if you worked on the .Net project.