diff -rupN sdk.2c798cbf6bf259ce49d94d91bc665a95d42d7a7f.orig/src/Cli/dotnet/Program.cs sdk.2c798cbf6bf259ce49d94d91bc665a95d42d7a7f/src/Cli/dotnet/Program.cs
--- sdk.2c798cbf6bf259ce49d94d91bc665a95d42d7a7f.orig/src/Cli/dotnet/Program.cs	2021-11-13 08:32:52.012563149 +0000
+++ sdk.2c798cbf6bf259ce49d94d91bc665a95d42d7a7f/src/Cli/dotnet/Program.cs	2021-11-13 08:33:32.414941596 +0000
@@ -171,7 +171,7 @@ namespace Microsoft.DotNet.Cli
                     bool generateAspNetCertificate =
                         environmentProvider.GetEnvironmentVariableAsBool("DOTNET_GENERATE_ASPNET_CERTIFICATE", defaultValue: true);
                     bool telemetryOptout =
-                      environmentProvider.GetEnvironmentVariableAsBool("DOTNET_CLI_TELEMETRY_OPTOUT", defaultValue: false);
+                      environmentProvider.GetEnvironmentVariableAsBool("DOTNET_CLI_TELEMETRY_OPTOUT", defaultValue: true);
                     bool addGlobalToolsToPath =
                         environmentProvider.GetEnvironmentVariableAsBool("DOTNET_ADD_GLOBAL_TOOLS_TO_PATH", defaultValue: true);
                     bool nologo =