On Tue, 08 Mar 2011 23:35:41 -0800 erikmccaskey64 <erikmccaskey64@xxxxxxxx> wrote: > If i want to block udp on dport 80 on the output chain, then is this > enough? i want to only allow tcp on it! iptables -P OUTPUT DROP > iptables -A OUTPUT -o $PUBIF --dport 80 -j ACCEPT > > > or i need this rule? > iptables -P OUTPUT DROP > iptables -A OUTPUT -o $PUBIF -p tcp --dport 80 -j ACCEPT > > > the second one is the good one? > > I think you need to use a a couple of rules like iptables -A OUTPUT -o $PUBIF -p !tcp --dport 80 -j DROP iptables -A OUTPUT -o $PUBIF -p tcp --dport 80 -j ACCEPT The first rule will drop anything not tcp on port 80. The second rule will accept anything tcp on port 80. If you only want to drop udp, change the first rule to iptables -A OUTPUT -o $PUBIF -p udp --dport 80 -j DROP iptables -A OUTPUT -o $PUBIF -p all --dport 80 -j ACCEPT If you are using an output rule that accepts everything outbound like the default Fedora firewall, you will have to put these rules in front of that. iptables -I OUTPUT -o $PUBIF -p tcp --dport 80 -j ACCEPT iptables -I OUTPUT -o $PUBIF -p !tcp --dport 80 -j DROP Note the reversed order, since these are being inserted instead of appended. -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
