A computer implemented method for retrieving in a client-server computer network a list of specific service instances among several service instances belonging to one or several types of services, each type of service being associated to a list of service instances, wherein the specific service instances are requested in a request for a specific service type made by a client via a client application, the method comprising: - a reception by a Domain Name System of the request for the specific service type, said request being forwarded by the client application to said DNS system; - a resolution of the request by said Domain Name System, wherein the resolution of the request comprises: 1) a determination, from information recorded in a DNS system memory of said DNS system and conveyed in said request, of a first type T 1 of service and of a first list L 1 of service instances associated to said first type T 1 of service; 2) a search for a linked structure comprised in a TXT resource record associated to said first type T 1 of service, wherein said linked structure is designed for determining and identifying another list L 2 of service instances associated to a subtype T 2 of service; 3) iterating for i = 2,...,N+1, N being the number of subtypes of services associated to the first type T 1 of service: if a linked structure and its corresponding subtype T i of service exist and are found, then searching for a linked structure comprised in a TXT resource record of said subtype T i of service, wherein said linked structure is designed for determining and identifying a list L i+1 of service instances associated to a subtype T i+1 of service. - a reception by a Domain Name System of the request for the specific service type, said request being forwarded by the client application to said DNS system; - a resolution of the request by said Domain Name System, wherein the resolution of the request comprises: 1) a determination, from information recorded in a DNS system memory of said DNS system and conveyed in said request, of a first type T 1 of service and of a first list L 1 of service instances associated to said first type T 1 of service; 2) a search for a linked structure comprised in a TXT resource record associated to said first type T 1 of service, wherein said linked structure is designed for determining and identifying another list L 2 of service instances associated to a subtype T 2 of service; 3) iterating for i = 2,...,N+1, N being the number of subtypes of services associated to the first type T 1 of service: if a linked structure and its corresponding subtype T i of service exist and are found, then searching for a linked structure comprised in a TXT resource record of said subtype T i of service, wherein said linked structure is designed for determining and identifying a list L i+1 of service instances associated to a subtype T i+1 of service. 1) a determination, from information recorded in a DNS system memory of said DNS system and conveyed in said request, of a first type T 1 of service and of a first list L 1 of service instances associated to said first type T 1 of service; 2) a search for a linked structure comprised in a TXT resource record associated to said first type T 1 of service, wherein said linked structure is designed for determining and identifying another list L 2 of service instances associated to a subtype T 2 of service; 3) iterating for i = 2,...,N+1, N being the number of subtypes of services associated to the first type T 1 of service: if a linked structure and its corresponding subtype T i of service exist and are found, then searching for a linked structure comprised in a TXT resource record of said subtype T i of service, wherein said linked structure is designed for determining and identifying a list L i+1 of service instances associated to a subtype T i+1 of service.