As with the previous NSKit release, the /var/yp/securenets file is now used to limit access to NIS services. If such a file exists on an NIS server, the server only answers queries or supplies maps to machines and networks whose IP addresses are listed in the file. For the file format, see the securenets man page.
The following is an example of a securenets file.
255.255.255.0 18.104.22.168 host 22.214.171.124 host 126.96.36.199
where 255.255.255.0 is the netmask and 188.8.131.52 is the network address. For the set up in line 1, ypserv responds to only those addresses in the subnet 184.108.40.206 range.
If you modify entries in the /var/yp/securenets file, you must kill and restart the ypserv and ypxfrd daemons.