This is a web.config file for doing reverse proxy with the ARR module from IIS. The configuration file was based on instructions from here: http://blogs.iis.net/carlosag/archive/2010/04/01/setting-up-a-reverse-proxy-using-iis-url-rewrite-and-arr.aspx

arr configuration.xml

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <system.web>
    <httpRuntime enableVersionHeader="false" />
  </system.web>
  <system.webServer>
    <rewrite>
      <rules>
        <rule name="Rewrite API" stopProcessing="true">
          <match url="^api\/(.*)$" />
          <action type="Rewrite" url="https://DESTINATION.COM/{R:1}" />
        </rule>
      </rules>
      <outboundRules>
        <preConditions>
          <preCondition name="IsRedirect">
            <add input="{RESPONSE_STATUS}" pattern="^30[1237]$" />
          </preCondition>
        </preConditions>
        <rule name="API Redirect" preCondition="IsRedirect" enabled="true">
          <match serverVariable="RESPONSE_Location" pattern="^(https?)://DESTINATION\.COM/(.*)" />
          <conditions>
            <add input="{URL}" pattern="^api\/.*$" />
            <add input="{HTTP_HOST}" pattern="^api\..*$" negate="true" />
          </conditions>
          <action type="Rewrite" value="{R:1}://{HTTP_HOST}/api/{R:2}" />
        </rule>
        <rule name="API Cookies" stopProcessing="true">
          <match serverVariable="RESPONSE_SET_COOKIE" pattern=".*" negate="false" />
          <conditions>
            <add input="{RESPONSE_SET_COOKIE}" pattern="^(ARRAffinity=.*;Domain=)DESTINATION\.COM.*$" />
          </conditions>
          <action type="Rewrite" value="{C:1}DESTINATION.COM" />
        </rule>
      </outboundRules>
    </rewrite>
    <caching enabled="false" enableKernelCache="false" />
    <httpProtocol>
      <customHeaders>
        <remove name="X-Powered-By" />
      </customHeaders>
    </httpProtocol>
    <security>
      <requestFiltering>
        <verbs>
          <add verb="OPTIONS" allowed="false" />
        </verbs>
      </requestFiltering>
    </security>
  </system.webServer>
</configuration>