Method for improving network configuration trustworthiness in a software defined network, SDN, comprising a plurality of SDN controllers that can receive network modification requests generated by SDN applications, and at least one SDN device that can receive network modification requests generated by the SDN controllers; comprising the steps of: - receiving a first network modification request (AppReq) generated by a SDN application (App 1); - selecting a plurality of controllers (C1,..., Cn); - supplying the first network modification request (AppReq) to the selected controllers; - generating a second network modification request in each selected controller when it receives the first network modification request (AppReq); - collecting second network modification requests (CtrReq1,.., CtrReqn) respectively generated by the selected controllers when they receive the first network modification request (AppReq), and assessing a trust value for this first network modification request (AppReq) as a function of the consistency of these second network modification requests (CtrReq1,.., CtrReqn); - and enforcing (6, 7) a third network modification request in at least one SDN device (S1,..., S4) if, and only if, the assessed trust value for this first network modification request (AppReq) is greater than a predetermined threshold; characterized in that, for assessing a trust value for this first network modification request (AppReq), it comprises the steps of: - receiving, from the selected controllers (C1,.., Cn), the generated second network modification requests (CtrReq1,..., CtrReqn) corresponding to said first network modification request (AppReq), - comparing each one of these second network modification requests (CtrReq1,.., CtrReqn) with another, and grouping them according to their similarities, so that similar second network modification requests are put into a same group, - assessing a consistency value for each group according to a given consistency policy, chosen as a function of the first network modification request, - filtering the groups according to their respective consistency values, and retaining the consistent groups only, - computing a respective trust level for each second network modification request (CtrReq1,.., CtrReqn), corresponding to said first network modification request (AppReq), and belonging to a consistent group, based on: (i) the relative number of the second network modification requests (CtrReq1,..., CtrReqn) having a same value, and (ii) trust levels respectively assigned to the controllers (C1,.., Cn) having generated the received second network modification requests; - comparing the trust levels of all the second network modification requests (CtrReq1,.., CtrReqn), and taking the highest one for constituting the trust level of the corresponding first network modification request. - receiving a first network modification request (AppReq) generated by a SDN application (App 1); - selecting a plurality of controllers (C1,..., Cn); - supplying the first network modification request (AppReq) to the selected controllers; - generating a second network modification request in each selected controller when it receives the first network modification request (AppReq); - collecting second network modification requests (CtrReq1,.., CtrReqn) respectively generated by the selected controllers when they receive the first network modification request (AppReq), and assessing a trust value for this first network modification request (AppReq) as a function of the consistency of these second network modification requests (CtrReq1,.., CtrReqn); - and enforcing (6, 7) a third network modification request in at least one SDN device (S1,..., S4) if, and only if, the assessed trust value for this first network modification request (AppReq) is greater than a predetermined threshold; - receiving, from the selected controllers (C1,.., Cn), the generated second network modification requests (CtrReq1,..., CtrReqn) corresponding to said first network modification request (AppReq), - comparing each one of these second network modification requests (CtrReq1,.., CtrReqn) with another, and grouping them according to their similarities, so that similar second network modification requests are put into a same group, - assessing a consistency value for each group according to a given consistency policy, chosen as a function of the first network modification request, - filtering the groups according to their respective consistency values, and retaining the consistent groups only, - computing a respective trust level for each second network modification request (CtrReq1,.., CtrReqn), corresponding to said first network modification request (AppReq), and belonging to a consistent group, based on: (i) the relative number of the second network modification requests (CtrReq1,..., CtrReqn) having a same value, and (ii) trust levels respectively assigned to the controllers (C1,.., Cn) having generated the received second network modification requests; (i) the relative number of the second network modification requests (CtrReq1,..., CtrReqn) having a same value, and (ii) trust levels respectively assigned to the controllers (C1,.., Cn) having generated the received second network modification requests; - comparing the trust levels of all the second network modification requests (CtrReq1,.., CtrReqn), and taking the highest one for constituting the trust level of the corresponding first network modification request.