TIL: Turn On Error Details In IIS

Ran into this today. Debugging a Coldfusion app on IIS, I'm having trouble getting any errors, despite having a nice Coldfusion error handler set up.

Turns out IIS was supressing these errors for security reasons. Nice for production, until you need to debug.

One: Add <customErrors mode="Off" /> to <system.web>

<system.web>
    <customErrors mode="Off" />
</system.web>

Two: Add <httpErrors errorMode="Detailed" /> to <system.webServer>

<system.webServer>
    <httpErrors errorMode="Detailed" /> 
</system.webServer>

Full web.config XML

And that's it! Here's my whole web.config for posterity.

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
    <system.web>
        <customErrors mode="Off" />
    </system.web>
    <system.webServer>
        <httpErrors errorMode="Detailed" /> 
    </system.webServer>
</configuration>

Source: Jim Tollan and Kasper Halvas Jensen on Stack Overflow