diff --git a/test/ServerComparison.TestSites.Standalone/Program.cs b/test/ServerComparison.TestSites.Standalone/Program.cs
index 02bbdd700c..0500b08856 100644
--- a/test/ServerComparison.TestSites.Standalone/Program.cs
+++ b/test/ServerComparison.TestSites.Standalone/Program.cs
@@ -1,6 +1,7 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Net.Http.Server;
@@ -13,7 +14,6 @@ namespace ServerComparison.TestSites.Standalone
         {
             var config = new ConfigurationBuilder()
                 .AddCommandLine(args)
-                .AddEnvironmentVariables(prefix: "ASPNETCORE_")
                 .Build();
 
             var builder = new WebHostBuilder()
@@ -24,7 +24,9 @@ namespace ServerComparison.TestSites.Standalone
             // Switch beteween Kestrel and WebListener for different tests. Default to Kestrel for normal app execution.
             if (string.Equals(builder.GetSetting("server"), "Microsoft.AspNetCore.Server.WebListener", System.StringComparison.Ordinal))
             {
-                if (string.Equals(builder.GetSetting("environment"), "NtlmAuthentication", System.StringComparison.Ordinal))
+                if (string.Equals(builder.GetSetting("environment") ??
+                    Environment.GetEnvironmentVariable("ASPNETCORE_ENVIRONMENT"),
+                    "NtlmAuthentication", System.StringComparison.Ordinal))
                 {
                     // Set up NTLM authentication for WebListener as follows.
                     // For IIS and IISExpress use inetmgr to setup NTLM authentication on the application or
diff --git a/test/ServerComparison.TestSites/Program.cs b/test/ServerComparison.TestSites/Program.cs
index e6d0dba35d..f272541cb8 100644
--- a/test/ServerComparison.TestSites/Program.cs
+++ b/test/ServerComparison.TestSites/Program.cs
@@ -4,6 +4,7 @@
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Net.Http.Server;
+using System;
 
 namespace ServerComparison.TestSites
 {
@@ -13,9 +14,8 @@ namespace ServerComparison.TestSites
         {
             var config = new ConfigurationBuilder()
                 .AddCommandLine(args)
-                .AddEnvironmentVariables(prefix: "ASPNETCORE_")
                 .Build();
-            
+
             var builder = new WebHostBuilder()
                 .UseConfiguration(config)
                 .UseIISIntegration()
@@ -24,7 +24,9 @@ namespace ServerComparison.TestSites
             // Switch beteween Kestrel and WebListener for different tests. Default to Kestrel for normal app execution.
             if (string.Equals(builder.GetSetting("server"), "Microsoft.AspNetCore.Server.WebListener", System.StringComparison.Ordinal))
             {
-                if (string.Equals(builder.GetSetting("environment"), "NtlmAuthentication", System.StringComparison.Ordinal))
+                if (string.Equals(builder.GetSetting("environment") ??
+                    Environment.GetEnvironmentVariable("ASPNETCORE_ENVIRONMENT"),
+                    "NtlmAuthentication", System.StringComparison.Ordinal))
                 {
                     // Set up NTLM authentication for WebListener as follows.
                     // For IIS and IISExpress use inetmgr to setup NTLM authentication on the application or