IIS custom errors not showing custom error page - asp.net

I have custom error pages setup on an ASP.NET website.
There is one error that is not showing a custom error page, and just showing the usual yellow ASP.NET error page. If custom errors are turned on it shows "Server error in / application" / "Runtime error", but if custom errors are off it shows "validation of viewstate mac failed" error.
The relevant parts of my web.config are:
<system.web>
<compilation debug="false" targetFramework="4.0" />
<customErrors mode="On" redirectMode="ResponseRewrite">
<error statusCode="404" redirect="/404.aspx" />
<error statusCode="500" redirect="/500.aspx" />
</customErrors>
<system.webServer>
<httpErrors errorMode="DetailedLocalOnly" />
To trap for this error do I have to use a different status code or substatuscode or is there something else?
NB. Server 2008 R2, IIS 7.

After further research I see that this means that IIS is displaying the error rather than ASP.NET.
I changed the system.webServer part of my web.config so IIS can also use the custom error page and that has solved the problem.
<system.webServer>
<httpErrors errorMode="Custom" existingResponse="Replace">
<remove statusCode="500" subStatusCode="-1" />
<error statusCode="500" subStatusCode="-1" responseMode="ExecuteURL" path="/500.aspx" />
</httpErrors>

Related

How to never show Yellow Error Page?

For security reasons (not to show .net framework version), I want to be sure that the asp.net yellow page (error page) is never displayed to a visitor.
What is the best practice?
Note that i used Custom as error mode for the httperrors but then:
- Do I have to declare all potential http errors? I could forget a status...
- Better way?
Sample of my web.config:
<httpErrors errorMode="Custom">
<remove statusCode="502" subStatusCode="-1" />
<remove statusCode="501" subStatusCode="-1" />
<remove statusCode="412" subStatusCode="-1" />
<remove statusCode="406" subStatusCode="-1" />
<remove statusCode="405" subStatusCode="-1" />
<remove statusCode="403" subStatusCode="-1" />
<remove statusCode="401" subStatusCode="-1" />
<remove statusCode="400" subStatusCode="-1" />
<remove statusCode="404" subStatusCode="-1" />
<remove statusCode="500" subStatusCode="-1" />
<error statusCode="404" path="/404Page.aspx" responseMode="ExecuteURL" />
<!-- ETC error for each status .... -->
</httpErrors>
This is what i have in my web.config for a project. It catches pretty much everything... You can have as many custom error codes as you want using this method.
<customErrors mode="On" defaultRedirect="pgError.aspx">
<error statusCode="504" redirect="pgNoConnection.aspx"/>
</customErrors>
I think that specifying a defaultRedirect would cause any error code to be redirected to this default page.
On this example all http error codes are redirected to GenericError.htm except for 500, that is redirected to InternalError.htm. You can remove the line that cause a different redirection to status code 500 and all error would go to the same page.
<configuration>
<system.web>
<customErrors defaultRedirect="GenericError.htm"
mode="RemoteOnly">
<error statusCode="500"
redirect="InternalError.htm"/>
</customErrors>
</system.web>
</configuration>
Here you have the complete MSDN reference for customErrors section
For not getting yellow page follow this steps copied from this Microsoft article:
(1) Design you custom Error page e.g Error.aspx
(2) With the error page completed, configure the web application to use the custom error page in lieu of the Runtime Error YSOD. This is accomplished by specifying the URL of the error page in the section's defaultRedirect attribute. Add the following markup to your application's Web.config file:
<configuration>
...
<system.web>
<customErrors mode="RemoteOnly"
defaultRedirect="~/ErrorPages/Oops.aspx" />
...
</system.web>
</configuration>
(3) By default, all types of errors cause the same custom error page to be displayed. However, you can specify a different custom error page for a specific HTTP status code using children elements within the section. For example, to have a different error page displayed in the event of a page not found error, which has an HTTP status code of 404, update the section to include the following markup:
<customErrors mode="RemoteOnly" defaultRedirect="~/ErrorPages/Oops.aspx">
<error statusCode="404" redirect="~/ErrorPages/404.aspx" />
</customErrors>

ASP.Net Swallowing 404 Error

So I've set up a rule in IIS7 to redirect to a specific page on a 404 error.
This works great as long as I'm typing URLs such as:
www.abc.com/Test/
However as soon as I attempt to access a file that doesn't exist
www.abc.com/Test/Test.aspx
I get the ASP.Net error message:
Server Error in '/' Application.
The resource cannot be found.
How can I keep ASP.Net from swallowing the 404 error and overriding my settings in IIS7?
EDIT: Here's my web.config file. IIS added the system.webServer stuff not me.
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<system.web>
<customErrors mode="Off"/>
</system.web>
<system.webServer>
<httpErrors>
<remove statusCode="403" subStatusCode="-1" />
<remove statusCode="404" subStatusCode="-1" />
<error statusCode="404" prefixLanguageFilePath="" path="/redir.aspx" responseMode="ExecuteURL" />
<error statusCode="403" prefixLanguageFilePath="" path="/redir.aspx" responseMode="ExecuteURL" />
</httpErrors>
</system.webServer>
</configuration>
If you're in Classic pipeline mode, you may be able to use the "Invoke handler only if request is mapped to file" option. I had to turn it on for two .aspx mappings--I think one was 32 bit and one was 64.

ASP.NET Application hosted on IIS7 that is ignoring custom errors and falls back to IIS errors

I have a C# web forms ASP.NET 4.0 web application that uses Routing for URLs for some reason custom errors defined in the system.web section of my web.config is entirely ignored and it will fall back the IIS errors.
This gets entirely ignored
<system.web>
<customErrors mode="On">
<error statusCode="500" redirect="~/Error" />
<error statusCode="404" redirect="~/404" />
<error statusCode="403" redirect="~/Error" />
</customErrors>
</system.web>
This part takes over
<system.webServer>
<httpErrors>
<!--<clear />-->
<remove statusCode="500" subStatusCode="-1" />
<remove statusCode="404" subStatusCode="-1" />
<error statusCode="404" subStatusCode="-1" path="/App1/404" responseMode="Redirect" />
<error statusCode="500" prefixLanguageFilePath="" path="/App1/Error" responseMode="Redirect" />
</httpErrors>
</system.webServer>
This would be a minor inconvenience except that by the fact it falls back to IIS native instead of my application it completely circumvents Elmah logging my 404 exceptions correctly.
Edit: Just to avoid any suggestions of such I only added the httpErrors configuration after customErrors stopped working so I would have anything.
To disable the IIS error messages you have to set
Response.TrySkipIisCustomErrors = true;
in your error page. After that, your Error messages should show without problem.
Instead of using:
Response.TrySkipIisCustomErrors = true;
Use this in Web.config:
<httpErrors errorMode="Custom" existingResponse="Replace">
You can pass through IIS7 default error messages in two ways
One is to set response.TrySkipIisCustomErrors = true
response.TrySkipIisCustomErrors = true;
response.Status = response.Status;
For some reason, TrySkipIisCustomErrors is not honoured if you don't set response.Status.
The other is to set existingResponse to "PassThrough" in web.config
<configuration>
<system.webServer>
<httpErrors existingResponse="PassThrough" />
</system.webServer>
</configuration>
But this will ignore all set IIS custom error pages.

IIS 7 Error Page for file with asp Extension

I have tried many ways but unable to do this. I have set the web.config as below.
<?xml version="1.0"?>
<configuration>
<system.webServer>
<asp scriptErrorSentToBrowser="true"/>
<httpErrors>
<remove statusCode="404" subStatusCode="-1" />
<error statusCode="404" prefixLanguageFilePath="" path="/index.asp" responseMode="ExecuteURL" />
</httpErrors>
</system.webServer>
<system.web>
<customErrors mode="On" defaultRedirect="index.asp">
</customErrors>
<compilation debug="false"/>
</system.web>
</configuration>
When I try this url
http://www.aboutmanchester.co.uk/wddwd.asp
It show a message not the error page I mention but when I try
http://www.aboutmanchester.co.uk/wddwd.aspx
I goes to the custom error page.
Is the application pool set to 'classic'?
http://technet.microsoft.com/en-us/library/cc753449%28WS.10%29.aspx
Is that an exact web.config copy? Without the errorMode="Custom" attribute on the httpErrors element I only get 404 pages to work with .aspx pages and get a generic IIS error page if I hit a issing .asp page. Adding the attribute gives me the expected behaviour.
<httpErrors errorMode="Custom">

Implementing a Custom Error page on an ASP.Net website

I have an ASP.Net website and I want to use a custom error page. I put the following code in my web.config
<customErrors mode="On" defaultRedirect="~/error.aspx">
<error statusCode="404" redirect="~/error.aspx" />
</customErrors>
The problem is when i go to a URL that does not exist is still uses the 404 error page specified in IIS Manager.
Question: How can I make it use the error.aspx page I have created? Why do the settings in IIS Manager override the web.config?
Try this way, almost same.. but that's what I did, and working.
<configuration>
<system.web>
<customErrors mode="On" defaultRedirect="apperror.aspx">
<error statusCode="404" redirect="404.aspx" />
<error statusCode="500" redirect="500.aspx" />
</customErrors>
</system.web>
</configuration>
or try to change the 404 error page from IIS settings, if required urgently.
There are 2 ways to configure custom error pages for ASP.NET sites:
Internet Information Services (IIS) Manager (the GUI)
web.config file
This article explains how to do each:
How To Set Up Custom Error Pages In IIS 7.5 With ASP.NET
The reason your error.aspx page is not displaying might be because you have an error in your web.config. Try this instead:
<configuration>
<system.web>
<customErrors defaultRedirect="error.aspx" mode="RemoteOnly">
<error statusCode="404" redirect="error.aspx"/>
</customErrors>
</system.web>
</configuration>
You might need to make sure that Error Pages in IIS Manager - Feature Delegation is set to Read/Write:
Also, this answer may help you configure the web.config file:
What is the difference between customErrors and httpErrors?
<customErrors defaultRedirect="~/404.aspx" mode="On">
<error statusCode="404" redirect="~/404.aspx"/>
</customErrors>
Code above is only for "Page Not Found Error-404" if file extension is known(.html,.aspx etc)
Beside it you also have set Customer Errors for extension not known or not correct as
.aspwx or .vivaldo. You have to add httperrors settings in web.config
<httpErrors errorMode="Custom">
<error statusCode="404" prefixLanguageFilePath="" path="/404.aspx" responseMode="Redirect" />
</httpErrors>
<modules runAllManagedModulesForAllRequests="true"/>
it must be inside the <system.webServer> </system.webServer>
<system.webServer>
<httpErrors errorMode="DetailedLocalOnly">
<remove statusCode="404" subStatusCode="-1" />
<error statusCode="404" prefixLanguageFilePath="" path="your page" responseMode="Redirect" />
</httpErrors>
</system.webServer>
Is it a spelling error in your closing tag ie:
</CustomErrors> instead of </CustomError>?

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