USRobotics NETServer/8 - Manual (Page 128)

8-14 Packet Filters
FTP Example 2
If you also wanted to allow external clients access to a specific
FTP server on your network, you could add a few more rules.
In this example, our FTP server is 192.77.203.12
set filter ftp.in 3 permit 0.0.0.0/0 192.77.203.12/32 tcp dst eq 21
set filter ftp.out 3 permit 192.77.203.12/32 0.0.0.0/0 tcp src eq 21 dst
gt 1023 established
set filter ftp.out 4 permit 192.77.203.12/32 0.0.0.0/0 tcp src eq 20 dst
gt 1023
set filter ftp.in 4 permit 0.0.0.0/0 192.77.203.12 tcp src gt 1023 dest
eq 20 established