protocol

The Protocol and port to use in the form [protocol]:[port_number] e.g. TCP:8080 or UDP:53. Conflicts with protocol_ports. Defaults to application-default.

NOTE In 4.0 or later versions, the default of protocol will no longer be set by provider, exactly one of protocol and protocol_ports must be specified. You need to explicitly specify protocol="application-default" to keep the the current default of the protocol.