Specifies the type of address for either performing a gethostbyname or a gethostbyaddr function at a remote host. Specification of dns(16) as the value for this object means that the gethostbyname function should be performed to return one or more numeric addresses. Use of a value of either ipv4(1) or ipv6(2) means that the gethostbyaddr function should be used to return the symbolic names associated with a remote host.