Sets the specified firewall rule entry protocol.
PRL_RESULT PrlFirewallRule_SetProtocol( PRL_HANDLE hRule, PRL_CONST_STR sProtocol );
PrlApiDeprecated.h
PRL_RESULT. Possible values:
PRL_ERR_INVALID_ARG - invalid handle or null pointer was passed.
PRL_ERR_SUCCESS - function completed successfully.