IIS 7 returns HTTP 200 on custom 404 error page

Question

I have successfully set up custom static error pages for IIS7. IIS7 is currently working as a gateway to a Java tomcat application. The issue is that when the 404 error page is served it is served with a HTTP 200 status code header. I would like a way to configure IIS to continue to send a HTTP 404. The error page exists as a static page in the webroot.

This is the main part of my web.config:

<system.webServer>
    <rewrite>
        <rules>
            <rule name="HTTP to HTTPS Redirect" enabled="true">
                <match url="(.*)" />
                <conditions>
                    <add input="{HTTPS}" pattern="off" />
                </conditions>
                <action type="Redirect" url="https://{HTTP_HOST}/{R:1}" redirectType="Found" />
            </rule>
            <rule name="Reverse Proxy" stopProcessing="true">
                <match url="(.*)" />
                <action type="Rewrite" url="http://localhost:8080/{R:1}" />
                <conditions>
                    <add input="{R:1}" pattern="error/*." negate="true" />
                </conditions>
            </rule>
        </rules>
    </rewrite>
    <httpErrors errorMode="Custom" existingResponse="Auto">
        <remove statusCode="404" subStatusCode="-1" />
        <error statusCode="404" prefixLanguageFilePath="" path="/error/404.htm" responseMode="ExecuteURL" />
    </httpErrors>
</system.webServer>

score 5 · Accepted Answer · answered Jun 26 '12 at 17:41

Switch to using responseMode="File" however the trick with this is going to be using relative file paths unless you unlock or set to true system.webServer/httpErrors allowAbsolutePathsWhenDelegated.

Example web.config excerpt:

<httpErrors>
    <remove statusCode="404" subStatusCode="-1" />
    <error statusCode="404" prefixLanguageFilePath="" path="error\404.htm" responseMode="File" />
</httpErrors>

score 1 · Answer 2 · answered Aug 13 '20 at 21:37

When using executeURL, the file should be something that renders dynamically (a la .asp). The file executed must contain a script that sets the response status code.

Example:

Change your 404.htm to 404.asp
Save the following code at the top of the 404.asp:

<% response.status = "404 Page Not Found" %>

score 0 · Answer 3 · answered Oct 20 '20 at 22:51

Have you tried changing ExecuteURL to Redirect in the responseMode attribute?

<httpErrors existingResponse="Replace" defaultResponseMode="Redirect" errorMode="Custom">
     <remove statusCode="404"/>
     <error statusCode="404" responseMode="Redirect" path="/index1.htm"/>          
</httpErrors>

Reference: https://techcommunity.microsoft.com/t5/iis-support-blog/issue-iis-logs-200-status-code-instead-of-404/ba-p/297652

IIS 7 returns HTTP 200 on custom 404 error page

3 Answers3