To get passive working properly, you need to do a few things:
- Make up a range between 1025 and 65535 .. (f.e. 3000-4000)
- Add that range to you firewall, so those ports are open (accepted)
- Now open the pure-ftpd config file and look for a line that says "PassivePortRange", uncomment this line and change it to: PassivePortRange 3000 4000
- restart pure-ftpd
If the ISPConfig filewall script is giving you a hard time use:
iptables -A INPUT -p tcp -m multiport --dports 3000:4000 -j ACCEPT
p.s. i would never use port numbers < 1024 for your own usage, since most of them are reserved for other services, which COULD lead to other problems.