Dynamic DNS providers offer a software client program that automates the discovery and registration of the client system's public IP addresses. The client program is executed on a computer or device in the private network. It connects to the DDNS provider's systems with a unique login name; the provider uses the name to link the discovered public IP address of the home network with a hostname in the domain name system. Depending on the provider, the hostname is registered within a domain owned by the provider, or within the customer's own domain name. These services can function by a number of mechanisms. Often they use an HTTP service request since even restrictive environments usually allow HTTP service. The provider might use RFC 2136 to update the DNS servers.