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I'm totally new to iptables but I need it to allow only ftp access to, and refuse the ftp connection to other domain/ip (by closing the port?).

Is this possible? how can I do that?

I googled for it but couldn't find a solution.

Thanks for your help :)

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up vote 1 down vote accepted
iptables -I FORWARD -p tcp -d --dport 21 -j ACCEPT
iptables -I FORWARD -p tcp --dport 21 -j REJECT

If you are not on a firewall system and you want to use the local iptables, it have to look like this:

iptables -I OUTPUT -p tcp -d --dport 21 -j ACCEPT
iptables -I OUTPUT -p tcp --dport 21 -j REJECT
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Thanks for the answer! What do you mean by "not on a firewall system ?" I will use the iptable from my only one server. – Cyril N. Jul 1 '11 at 12:10
@cx42net You could have a dedicated firewall system / router. In your case, use the second one – Thomas Berger Jul 1 '11 at 12:14
Thanks for the precision! :) – Cyril N. Jul 1 '11 at 12:34
I've got an error when I write the first line of the second solution : "iptables: No chain/target/match by that name.". Do you know why? – Cyril N. Jul 1 '11 at 13:48
@cx42net make sure you have installed the iptables packages of your distribution and the kernel modules are present. If they are missing, you will get an error like this. – Thomas Berger Jul 1 '11 at 13:58

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