On CentOS 6.6-
At first, iptables was blocking access to my FTP server at all while it was on. After some research I added the lines to
/etc/sysconfig/iptables
that are suggested in the question Iptables to allow incoming FTP and it works... for about 2 minutes, then I can no longer connect to my server. If I then
/sbin/service iptables stop
/sbin/service iptables start
It will work again... for a few minutes. This is infuriating.
Any help is appreciated thank you.