Preserves the client's original IP address across load balancers or application gateways.
First, install the assembly in the GAC with Chocolatey.
choco install ai-web-originalip
If you have IIS installed, it will call iisreset
Next, open up a command prompt in admin mode use appcmd to add a managed module to your site.
c:\windows\system32\inetsrv\appcmd add module /name:OriginalIP /type:"Added.Web.Core.Modules.OriginalIP, Added.Web.Core, Version=1.0.0.0, Culture=neutral, PublicKeyToken=94825510554e74d3" /preCondition:runtimeVersionv4.0,managedHandler /app.name:"Default Web Site/"
Change the /app.name parameter to the web site you need. If you leave the parameter off, it will apply it to all sites in IIS.