Support for bypassing host name lookup in otelnetd

In z/OS® V1R13 Communications Server, the z/OS UNIX Telnet server (otelnetd) has a new parameter that controls the lookups of the gethostbyaddr and getnameinfo routines. If you specify the new -g parameter, otelnetd will not issue the gethostbyaddr or getnameinfo routines to resolve the client IP address. If the domain name server (DNS) is not responding to the resolver in a timely manner, you can use the new otelnetd parameter to avoid delays in connecting to otelnetd caused by the hostname lookup.

Restriction: The -g parameter is ignored when the -U parameter is specified. The -U parameter causes otelnetd to drop connections from any IP address that cannot be mapped back into a symbolic name by the gethostbyaddr or getnameinfo routines.