The config.winrm namespace is used to configure Vagrant when using a Windows guest machine. To use these settings, you must set your config.vm.communicator setting to winrm.

There are around 12 different configuration options available, which include config.winrm.username, config.winrm.password, config.winrm.port, and config.winrm.transport. Using the config.winrm namespace gives you much more control over how Vagrant behaves when using a Windows guest machine.