A wrapper is a program used in Transmission Control Protocol (TCP) to provide a layer of security by intercepting calls to computer services and determining whether the service is authorized to execute. A wrapper provides the necessary protection against host name and host address spoofing. The determination of whether to provide access to requests is done with the help of a system administrator, who adds entries in the TCP wrapper configuration files /etc/hosts.allow and /etc/host.deny after installing the wrapper program.