Hi, after updating one of my systems to 5.7 FTP connections stopped working. After a bit of debugging I found out that the ip_nat_ftp module apparently breaks things in 5.7.
So I you update your systems and suddenly FTP starts acting up check if you have that module in /etc/sysconfig/iptables-config.
Details: http://bugs.centos.org/view.php?id=5135
Regards, Dennis