The hosts.lpd file provides:
A list of network printer IP addresses.
A listening of printers available on the local network.
A listening of computers that have printer (lpd) daemons running.
A listening of hosts allowed to use printers on the local machine.
A list of hosts on the local network that are not allowed access to printers attached to the local
The /etc/hosts.lpd file defines which remote systems are permitted to print on the local system.
Only that hosts specified in /etc/hosts.lpd can send the printing job.
See the output of /etc/hosts.lpd
Only station1, 2 and 3 can send the print job.