The Restricted setting indicates that the NetBackup host first attempts to perform reverse host name lookup. If the NetBackup host successfully resolves the IP address of the connecting server to a host name (reverse lookup is successful), it compares the host name to the list of known server host names.

If the resolution of the IP address to a host name fails (reverse lookup fails), based on the Restricted setting, the host converts the host names of the known server list to IP addresses (using a forward lookup). The host compares the IP address of the connecting server to the list of known server IP addresses.

If the comparison fails, the host rejects the connection from server and the connection fails.