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Remove IIS Server version HTTP Response Header

Remove HTTP response headers in IIS 7, 7.5, 8.0, 8.5, 10 and ASP.NET

Windows Server IIS loves to tell the world that a website runs on IIS. It does so with the Server header in the HTTP response, as shown below. In this post I’ll show you how to remove response server headers in IIS. You don’t want to give hackers too much information about your servers, heh? ;-).

Microsoft Internet Information Services logo
Microsoft Internet Information Services

Normal HTTP Response headers

Even though I’m not a big fan of security by obscurity (are you?), removing common server response headers is often advised by security experts. Attackers might gain a lot of information about your server and network, just by looking at the response headers a web server returns.

Therefore it’s advised you remove at least some of them.

But let’s start with how a normal HTTP HEAD response looks like:


HTTP/1.1 200 OK
Content-Length: 0
Content-Type: text/html; charset=UTF-8
Vary: Accept-Encoding
Server: Microsoft-IIS/8.0
X-UA-Compatible: IE=Edge,chrome=1
Date: Sun, 06 Jul 2014 10:05:34 GMT
Connection: close

Here you notice IIS displaying its version information in a Server header, as response:


Server: Microsoft-IIS/8.0

As with removing ETag headers in IIS, you can rewrite and empty the Server: HTTP response header in IIS with a URL Rewrite outboundRule.

Remove Server response header with an outboundRule URL Rewrite rule

Unfortunately you cannot really remove the Server header. But you can rewrite its content and empty it.
On IIS 7+ (IIS 7, 8.5, 8.0, 8.5), use an rewrite outboundRule to remove the web server version information from the Server: header response.

You can use the following URL Rewrite Outbound rule:


<rewrite>    
  <outboundRules rewriteBeforeCache="true">
    <rule name="Remove Server header">
      <match serverVariable="RESPONSE_Server" pattern=".+" />
      <action type="Rewrite" value="" />
    </rule>
  </outboundRules>
</rewrite>

What the outboundRule does is: it looks for the header – or serverVariable – Server: in the output response stream, and rewrites the value with an empty string (nothing).

The end result is an empty Server: response header line:


HTTP/1.1 200 OK
Content-Length: 0
Content-Type: text/html; charset=UTF-8
Vary: Accept-Encoding
Server:
X-UA-Compatible: IE=Edge,chrome=1
Date: Sun, 06 Jul 2014 10:06:08 GMT
Connection: close

You’ve now successfully removed the Server version response from the HTTP headers!

This is a website-specific rule. If you want to create the rule for all of your applications, you have to create the rule at the server level. Also, some applications, especially third party applications, may require and depend on the Server header. Then you may need to remove this rule for those applications.

Rewrite ‘Server: Microsoft-IIS/8.0’ with your own server information – just for the fun

The fun part of rewriting response headers is that you can display your own information string. For example, if you give in an value in the Rewrite action, that message is displayed:


<action type="Rewrite" 
  value="Saotn Server Software systems, LTD." />

HTTP/1.1 200 OK
Content-Length: 0
Content-Type: text/html; charset=UTF-8
Vary: Accept-Encoding
Server: Saotn Server Software systems, LTD.
X-UA-Compatible: IE=Edge,chrome=1
Date: Sun, 06 Jul 2014 11:19:16 GMT
Connection: close

Fun, heh πŸ™‚

Remove ASP.NET X-Powered-By header in IIS using web.config customHeaders

By default IIS tells the world it’s powered by ASP.NET, by placing an X-Powered-By header:


HTTP/1.1 200 OK
Content-Length: 0
Content-Type: text/html; charset=UTF-8
Vary: Accept-Encoding
Server:
X-Powered-By: ASP.NET
X-UA-Compatible: IE=Edge,chrome=1
Date: Sun, 06 Jul 2014 10:07:37 GMT
Connection: close

This response header can be removed with a customHeaders setting in web.config, placed in the <system.webServer> node:


<httpProtocol>
  <customHeaders>
    <remove name="X-Powered-By" />
  </customHeaders>
</httpProtocol>

Now the X-Powered-By header is removed from the response header output


HTTP/1.1 200 OK
Content-Length: 0
Content-Type: text/html; charset=UTF-8
Vary: Accept-Encoding
Server:
X-UA-Compatible: IE=Edge,chrome=1
Date: Sun, 06 Jul 2014 10:10:02 GMT
Connection: close

X-AspNet-Version header

The X-AspNet-Version HTTP Header broadcasts to the world what version of ASP.NET is being used. Add the following content inside the <system.web> node in your application’s web.config file:


<httpRuntime
  enableVersionHeader="false" />

Azure: How to remove ‘Server’ and ‘X-Powered-By’ response headers from your Azure websites

You can now hide the Server and X-Powered-By headers by adding an entry to your web.config system.webServer node:


<security>
  <requestFiltering removeServerHeader ="true" />
</security>

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34 Comments

  1. Thanks Jan. Great article i removed iis server headers successfully.

  2. Ulli

    To remove all instances of the header (incl. on 404, etc. responses) or for self hosted services:
    https://blogs.msdn.microsoft.com/dsnotes/2017/12/18/wswcf-remove-server-header/

  3. Ankit

    Hi,

    I am getting the Server Name as “Microsoft-IIS/8.5” even after rewriting the server name as “” in the Error pages. Following is the web.config code:

    • Hi Ankit,

      Unfortunately your web.config code got lost in the comment. But what do you mean with “in the Error pages”, like the default IIS error pages located in C:\inetpub\custerr\en-US? Or somewhere else? Perhaps you have to use existingResponse=passthrough too? See the other comments.

      • Ankit

        Hi Jan,

        I am redirecting the error to the custom error pages like

        and I am using the following to remove/rename the Server Name:

        But, then also Server Name is coming in the custom error pages. How to remove the server name from the custom error pages?

        • Hi Ankit,
          Your code isn’t coming through, please use a gist if possible and link to there, or wrap your code nicely in `<code></code>` tags.

          • Ankit

            Hi Jan,

            Thanks for the advice. I hope this time my code is visible.

            I am developing a mobile friendly application using MEAN. So. my issue is that I want to remove/hide/rename the Server Name from all the pages. I am able to do so in all the pages except the custom error pages. I am redirecting the error to the custom error pages like:

            and I am using the following to remove/rename the Server Name:

            But, then also Server Name is coming in the custom error pages. How to remove the server name from the custom error pages?

          • ANKIT

            Hi Jan,

            Actually, the issue is that the server name is visible in the HTTP Headers. Using the outbound rule in web.config, the server name is removed from the web pages but it is not removed from the custom error pages to which I am redirecting. I have also used errorMode=”Custom” existingResponse=”PassThrough” but it’s still coming.

  4. Rikin Patel

    When I used below code

    protected void Application_BeginRequest(object sender, EventArgs e)
    {
    var application = sender as HttpApplication;
    if (application != null && application.Context != null)
    {
    application.Context.Response.Headers.Remove(“Server”);
    }
    }
    Then I am getting following error.
    Error: This operation requires IIS integrated pipeline mode

    More Info: I am using IIS 10, website hosting as Application and Application pool as Classic mode. If I changed to Integrated mode then working fine. But right now I can not change to this on Production environment because it may create other issue.

    So, can you please suggest best solution in this situation.

    • Hi Rikin, thank you for your comment!

      I’m not a fan of Classic mode application pools. Why would you want to have IIS 6.0 behaviour? I’d say, fix the problems you have switching to Integrated mode, and move on from there turning off response headers. If Integrated mode is really not an option, try to use web.config settings to disable headers.

      HTH!

  5. Anonymous

    Thanks for the help!

  6. I also have a rule that redirects http requests to https. But the redirect sends back all headers, including the Server: header. This is the http rule:

    This is from the Microsoft URL Rewrite reference page:

    Usage of a Redirect action implies that no subsequent rules evaluated for the current URL after redirection is performed.

    Is there any way to remove the server header on a redirect?

  7. I am using IIS 8.5 and whenever I attempt to use in my web.config IIS does not like it. I’ve seen that this only works on IIS7 or other versions. Is there a workaround or other method to remove the ASP version?

  8. Nishant

    Removing the server variable from response using url rewrite outbound rules is not working . application is angular 4 application and My server is windows 8 with iis 8.5 and I have my web.config data as shown below .

  9. PRS

    what is the impact,if application caching having both
    Custom HTTP Response Header +set common HTTP response header

  10. AErot

    Hi, great article, but I’ve got question/problem..

    At the first glance all seems be well, I receive modified http headers, but when I send request to doesn’t exists page (and server will return 404 webpage) server name is ‘IIS 8.5’ in the HTTP headers..

    I found what is a problem – custom error pages.

    When I remove httpErrors elements from web.config, Server Name header isn’t display in HTTP headers (in both cases – correct/incorrect webpage url).

    How can I fix it ? (I want to have custom error pages and remove Server Name header..)

    Regards
    AErot

    • Hi @disqus_E1570bwNoJ:disqus , thank you for your comment. Interesting… What are you using, PHP or ASP.NET, and which solution do you use to remove the Server: header? It might be a .NET Framework thingy.

      • AErot

        Hi Jan R, thanks for quick response. I use your method: URL Rewrite Module Outbound Rule on IIS8. Actually I created topic on forums.iis.net ( http://forums.iis.net/t/1233506.aspx?How+to+remove+Server+Name+Microsoft+IIS+8+5+from+HTTP+headers+ ) (where is my config file), but I have not received accurate answer yet.

        I’m still looking for help..

        Regards
        AErot

        • I’ve seen your web.config in that thread. Maybe you have to add existingResponse= to your custom httpErrors node? See http://stackoverflow.com/a/31041696/1297898 for more information.

          • AErot

            Bullseye! It looks like it’s working with Passthrough πŸ™‚ I must think about error page in ASP.NET. Thx!

            Best
            AErot

          • Nice find @disqus_E1570bwNoJ:disqus , if you have the relevant web.config lines for me (and the scripting language you use: ASP.NET, PHP or ASP), I can add it to this post. Thanks in advance!

          • Vijaikanth N

            Hi,

            When i set the existingResponse=passthrough, the server information is not displayed for the 404 status code but my custom error pages defined in IIS stopped working. Is there any workaround for this?

  11. Ansonmus

    We have tried it. But it doen’t work. Probably because of this line (MVC…): routes.IgnoreRoute(“{resource}.axd/{*pathInfo}”);

  12. Ansonmus

    Thanks for the answer, do you have any idea how to fix this?

  13. Ansonmus

    I’ve a issue with the solution.
    I can do a request to /blalbla.axd (every name possible) and then the “Server” variable will have a value…

    • Hi Ansonmus, thanks for your comment.
      The .axd file type is handled by the .NET Framework and often falls beyond the scope of URL Rewrite.

  14. This article was very helpful. The $2 donation is worth it.

  15. Kunal Maurya

    Is there any way to completely remove “Server: Microsoft-IIS/8.0” from a site having static pages only like ?

    • Hi Kunal, thank you for your comment.
      An IIS Outbound Rule rewrites the output stream (HTTP response), so it’ll also remove the Server header from static HTML files.

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