In console app scenario, the same is achieved by setting in your application configuration file. This suggests our WCF application would choose TLS1.2 if OS is configured properly. If not, it will fall back to 4.5 default behavior, it means to select SS元.0 and TLS1.0 as default protocols. To Target 4.7.1, we need to set in web.config. If you are targeting your application to 4.7.1, WCF is configured to allow the OS to choose the best security protocol by default unless explicitly configured.
NET Framework 4.7.1, WCF defaults to the operating system configured version, WCF Supports TLS1.0, 1.1 and 1.2 as the default in.