A server computer (DNPS) for commissioning/decommissioning networks and provisioning said networks to an orchestration system constituting a client-server architecture with the server computer (DNPS), the server computer (DNPS) comprising: - a database comprising data; - a remote user interface for remote management of the server computer (DNPS), wherein the remote user interface provides access to the data in the database; - a network-based application programming interface supporting service oriented architecture ["SOA"] to a client of the orchestration system; and - a network management engine for dynamically assigning and releasing networks and provisioning said networks to the client of the orchestration system, wherein the network management engine is connected to the database, the remote user interface and the network-based application programming interface, the network management engine Z being configured to receive, from the orchestration system, a request in which a network is requested characterised in that the network management engine is configured to perform: checking (2-4, 2-10) whether the request includes a customer or tenant name tagged, in the server computer (DNPS), to a network block managed by the server computer (DNPS), the network block comprising prefixes, networks and associated administrative data; in response to the request including said customer or tenant name tagged to the network block (2-4, 2-10), performing the following: in response to the request including an IP address or a netmask, checking whether the requested network and/or netmask is available in the network block tagged with said customer or tenant name, and, if said requested network and/or netmask is available, reserving the requested network from the network block tagged with said customer or tenant name and returning it to the orchestration system, in response to the request failing to include either an IP address or a netmask, checking whether a default netmask is configured to the server computer (DNPS) and, if a default netmask is configured the server computer (DNPS), whether said default netmask is available in the network block tagged with said customer or tenant name, and, if said default netmask is available, reserving the requested network from the network block tagged with said customer or tenant name and returning it to the orchestration system; and in response to the request failing to include said customer or tenant name tagged to the network block (2-4, 2-10), performing the following: in response to the request including an IP address or a netmask, checking whether the requested network and/or a public network of a size of the netmask is available in a private or public network block managed by the server computer (DNPS), and, if the requested network and/or said public network is available, reserving a network deemed to be available and returning it to the orchestration system, and in response to the request failing to include an IP address or a netmask, checking whether a default netmask is configured to the server computer (DNPS) and, if the default netmask is configured, whether a network with a size of the default netmask is available in at least one public network block managed by the server computer (DNPS), and, if the network with the size of the default netmask is available, reserving the network with the size of the default netmask and returning it to the orchestration system. - a database comprising data; - a remote user interface for remote management of the server computer (DNPS), wherein the remote user interface provides access to the data in the database; - a network-based application programming interface supporting service oriented architecture ["SOA"] to a client of the orchestration system; and - a network management engine for dynamically assigning and releasing networks and provisioning said networks to the client of the orchestration system, wherein the network management engine is connected to the database, the remote user interface and the network-based application programming interface,