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Old 22nd August 2008
J65nko J65nko is online now
Join Date: May 2008
Location: Budel - the Netherlands
Posts: 3,798

ftp uses 2 separated connections
  1. A command channel, where the ftp client uses port 21 as the destination port.

  2. A data channel, where in passive mode the ftp client uses a destination port >1023 as suggested by the ftp server.
    In active mode the server initiates this channel using source port 20, which usually is a not liked and thus not allowed by most system administrators.

Since my house move I don't have access to a FBSD box, but in OpenBSD the ports suggested by the ftp server for passive ftp channels is set by the following sysctls in blue
Re: ftp-proxy

ftp-proxy needs to run on a dedicated pf firewall with 2 NICs. It can neither run on a ftp client box, nor on a ftp server box.
You don't need to be a genius to debug a pf.conf firewall ruleset, you just need the guts to run tcpdump
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