An appliance and method for authorizing a level of access of a client to a virtual private network connection, based on a client-side attribute includes the step of establishing, by an appliance, a control connection with a client upon receiving a client request to establish a virtual private network connection with a network. The appliance transmits, via the control connection, a request to the client to evaluate at least one clause of a security string, the at least one clause including an expression associated with a client-side attribute. The client transmits, via the control connection, a response to the appliance comprising a result of evaluating the at least one clause by the client. The appliance assigns the client to an authorization group based on the result of evaluation of the at least one clause.