Iptables problem

Using 
iptables -A INPUT -p tcp -dport 20 -j ACCEPT
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[Patrick O'Callaghan]

On Sat, 2013-03-09 at 13:23 +0000,
[e-mail] wrote:
> Using 
> iptables -A INPUT -p tcp -dport 20 -j ACCEPT
> Sent from my BlackBerry® smartphone powered by Mobilicity

If you don't state what the problem actually was, I doubt that anyone
can help you.

poc

[Reindl Harald]

Am 09.03.2013 14:23, schrieb [e-mail]:
> Using 
> iptables -A INPUT -p tcp -dport 20 -j ACCEPT

this is a useless problem description at all
since our glass balls are broken

20 is active FTP and will not work until the client's
firewall opens the random port of the ftp-client while
for passive ftp on port 21 the server tells the client
his random port and is responsible via conntrack to allow
the data connection

in other words: these days nobody is using active FTP

here some basics stuff:
http://fetchsoftworks.com/fetch/help/Contents/Concepts/ActiveAndPassive.html