[gate:~] # cd /usr/ports/ftp/frox/

[gate:ports/ftp/frox] # make config

...
 PF [X]
...

[gate:ports/ftp/frox] # make install clean

[gate:~] # cp /usr/local/share/examples/frox/frox.conf /usr/local/etc/

[gate:~] # rcsdiff /usr/local/etc/frox.conf
22c22
< Listen 192.168.2.1
---
> Listen 192.168.X.1
97c97
< # LogFile /usr/local/lib/frox/frox-log
---
> LogFile /val/log/frox-log
186,187c186,187
< # CacheModule http
< # HTTPProxy 127.0.0.1:3128
---
> CacheModule http
> HTTPProxy 127.0.0.1:3128

[gate:~] # cat /etc/pf.conf
...
rdr proto tcp from 192.168.13/24 to any port 21 -> 192.168.X.1 port 2121
...

[gate:~] # rcsdiff /usr/local/etc/squid/squid.conf
665a666
> http_access allow localhost

В клиенте необходимо настроитть Passive FTP