Security Basics mailing list archives

WuFTP server with Iptables.


From: "Jari IT" <jari_info () yahoo uk co>
Date: Sat, 25 Sep 2004 14:55:18 +1000


Hi all,

I am setting a FTP server with Iptable firewall.
Here is the rule, which I get from www.openna.com.


    # incoming request
    iptables -A INPUT  -i $EXTERNAL_INTERFACE -p tcp  \
             --source-port $UNPRIVPORTS \
             -d $IPADDR --destination-port 21 -j ACCEPT

    iptables -A OUTPUT -o $EXTERNAL_INTERFACE -p tcp ! --syn \
             -s $IPADDR --source-port 21 \
             --destination-port $UNPRIVPORTS -j ACCEPT


    # PORT MODE data channel responses
    iptables -A OUTPUT -o $EXTERNAL_INTERFACE -p tcp  \
             -s $IPADDR --source-port 20 \
             --destination-port $UNPRIVPORTS -j ACCEPT

    iptables -A INPUT  -i $EXTERNAL_INTERFACE -p tcp ! --syn \
             --source-port $UNPRIVPORTS \
             -d $IPADDR --destination-port 20 -j ACCEPT


    # PASSIVE MODE data channel responses
    iptables -A INPUT  -i $EXTERNAL_INTERFACE -p tcp  \
             --source-port $UNPRIVPORTS \
             -d $IPADDR --destination-port $UNPRIVPORTS -j ACCEPT

    iptables -A OUTPUT -o $EXTERNAL_INTERFACE -p tcp ! --syn \
             -s $IPADDR --source-port $UNPRIVPORTS \
             --destination-port $UNPRIVPORTS -j ACCEPT

However, I still cannot connect from my house (behind ADSL router/modem) to
that site.
Stop this firewall, the FTP server work well.

Please advice me about this.
Thanks in advance,
Jari




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