Thank you pal... Juan On Thu, 2003-11-27 at 12:04, Ralf Spenneberg wrote: > Am Don, 2003-11-27 um 16.41 schrieb Juan Hernandez: > > > 1) This rule tells netfilter to drop any packet forwarding I guess > > iptables -P FORWARD DROP > This is a default rule. All packets not accepted or dropped by other > rules will be dropped by this one. > > > > > 2) This one only accepts related and stablished packets > > iptables -A FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT > correct. > > > 3) This one forwards everything from the mailserver to the outside i > > guess > > iptables -A FORWARD -d 192.168.0.2 -p tcp --dport 25 -j ACCEPT > No. This allows all packets destined for 192.168.0.2:25 through. > > > 4) and this rule redirects everything in port 25 to the mailserver > > iptables -t nat -A PREROUTING -d 192.168.0.1 -p tcp --dport 25 -j DNAT > > --to-destination 192.168.0.2:25 > This rule redirects all packets targeted at 192.168.0.1:25 to 192.168.0.2:25. > > > Now these are the questions I have about netfilter > > > > 1) What does the first rules do exactly?? > > > > 2) How come if I add this rule to redirect everything from port 666 to > > the mailserver's ssh port it doesnt work?? > > > > iptables -t nat -A PREROUTING -d 192.168.0.1 -p tcp --dport 666 -j DNAT > > --to-destination 192.168.0.2:22 > You need a rule which will allow these packets through the FORWARD > chain: > iptables -A FORWARD -d 192.168.0.2 -p tcp --dport 22 -j ACCEPT > > > 3) How do I use DROP with a range of port in oder to close everyhing > > else to the outside? or is there other way to do it?? > Everything else is closed by the Default rule (1) > > Cheers, > > Ralf
