HP-UX IPFilter A.03.05.13 Administrator's Guide: HP-UX 11i v3

Table Of Contents
HP-UX IPFilter and FTP
Running an FTP Server
Chapter 7116
To use IPFilter to protect passive FTP sessions, you must limit the port
range your system can use for FTP access. For example, you can allocate
ports 15001-15500 as FTP ports and only open up that range of your
firewall. In WU-FTPD, you use the passive ports directive in the
/etc/ftpaccess configuration file to designate the ports, as follows:
passive ports
<server-ip>
15001 15500
See the ftpaccess (4) manpage for details on WU-FTPD configuration.
Configure the following IPFilter rules to let the passive FTP traffic pass:
pass in quick proto tcp from any port > 1023 to
<server-ip>
port = 21 flags S keep state
pass in quick proto tcp from any port > 1023 to
<server-ip>
port 15000 ><15501 flags S keep state
block in from any to any
block out from any to any