How to repair web.config file

You may find that your DualShield IIS agent stops working after applying an Exchange server CU upgrade. This is because the Exchange CU upgrade will reset  all web applications settings, i.e. the "web.config" file, hence cause the settings for the DualShield IIS agent to  be lost.  

You can restore the DualShield IIS Agent settings in 2 ways, manually or by a PowerSheel script.

Manual

This has to be done on every IIS node that is enabled with DualShield 2FA. Let's use OWA as an example. In the IS Manager, navigate to the OWA node:

Right click it, then choose "Explore"

It will take you to the physical folder, C:\Program Files\Microsoft\Exchange Server\V15\FrontEnd\HttpProxy\owa. 

Now, open web.config in a text editor, find the <modules> tag and insert <add name="DasIIS7Native"/> into the tag, e.g:

<modules>
<add name="DasIIS7Native"/>
</modules>

Below is a complete sample:

<?xml version="1.0" encoding="UTF-8"?>
<configuration
<!-- .... -->
<configSections>
<section name="microsoft.identityModel" type="Microsoft.IdentityModel.Configuration.MicrosoftIdentityModelSection, Microsoft.IdentityModel, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
</configSections>
<location inheritInChildApplications="false">
<system.webServer>
<serverRuntime appConcurrentRequestLimit="65535" uploadReadAheadSize="0"/>
<modules>
<add name="DasIIS7Native"/>
<!-- .... -->
</modules>
</system.webServer>
</location>
<!-- .... -->
</configuration>

PowerShell Script

#http://mvolo.com/anatomy-of-an-iis7-configuration-path/
[settings]$dualconf = Get-Content Settings.xml

foreach( $item in $dualconf.settings.list.item) 
{
if($item.protected -eq "yes"){
$metapath = $item.path -replace "/LM/W3SVC/1/Root/", "MACHINE/WEBROOT/APPHOST/Default Web Site/"
# write-host $metapath 
Enable-WebGlobalModule -Name "DasIIS7Native" -PSPath $metapath
}

}