<application>IPF
</application> has a built in
<acronym>FTP
</acronym> proxy which can be used with
<acronym>NAT
</acronym>. It monitors all outbound traffic for active or passive
<acronym>FTP
</acronym> connection requests and dynamically creates temporary filter rules containing the
port number used by the
<acronym>FTP
</acronym> data channel. This eliminates the need to open large ranges of high order
ports for
<acronym>FTP
</acronym> connections.