If you are behind a firewall and you want to narrow the range of ftp Passive Ports, run this:
echo "29799 29899" > /etc/pure-ftpd/conf/PassivePortRange
where 29799 29899 is your port range. this configuration is for 50 clients. and yes, you need to have 2 ports for each client.
You might also consider creating a config for max clients:
echo "50" > /etc/pure-ftpd/conf/MaxClientsNumber
Restart pure-ftp-mysql:
/etc/init.d/pure-ftpd-mysql restart
Resources: www.howtoforge.com
