customErrors with redirectMode="ResponseRewrite" do not work on shared hosting

Question

I am trying to setup custom error pages for my site (ASP.NET 4, integrated pipeline).

Everything works properly on local machine but custom error pages for .aspx pages do not get shown on shared hosting (I see default error pages).

If I change redirectMode="ResponseRewrite" to redirectMode="ResponseRedirect" everything works properly on local and shared machine.

error.aspx is a real file that resides next to web.config file (in the root of the site). Site has no Global.asax file.

Local machine runs IIS 7.5, I do not use routing (at least consciously) and shared hosting tells that Server: Microsoft-IIS/7.5 X-AspNet-Version: 4.0.30319

Could you please tell me what might be the reason for such different behavior and what should I do to resolve the issue.

Here is excerpt from my web.config file:

<system.webServer>
    <httpErrors errorMode="Custom">
        <remove statusCode="404" />
        <error statusCode="404" path="/error.aspx" responseMode="ExecuteURL" />      
    </httpErrors>
</system.webServer>
<system.web>
    <customErrors mode="On" defaultRedirect="error.aspx" redirectMode="ResponseRewrite">
        <error statusCode="404" redirect="~/error.aspx"/>
    </customErrors>
    <httpRuntime requestValidationMode="2.0" />
</system.web>

Answer 1

After loooong discussion with the hosting provider it turned out that:

• my approach is fine
• but it won't work as expected because hosting provider disabled such ability via machine.config.

So, never underestimate number of provider gotchas.

Answer 2

I have the following comment in my web.config:

for IIS 7.5, use errorMode="Custom"; use responseMode="ExecuteURL" if using routing, otherwise use responseMode="Redirect"

Just don't ask me to explain, because I don't know! I just sorted it out by trial and error.