Re: portforwarding-HOWTO

["Linux" <linuxrobotsstayaway@usermail.com>]

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Linux303
----- Original Message -----
From: <oarojo@intermediacorp.com>
To: <netfilter@lists.netfilter.org>
Sent: Sunday, January 05, 2003 11:50 PM
Subject: portforwarding-HOWTO


> Hello people!!!
>
> I have set-up a linux box firewall with two ethernet cards; eth0 facing
the
> internet and eth1 facing the internal network. Inside my network is my
mail
> server with an IP of 192.168.0.5. Now since my ISP had only given me one
> valid IP address for my network, I wish to do port-forwarding for ports 25
> and 110. I did something like:
>
> # iptables -t nat -A PREROUTING -p tcp -i eth0 -d xxx.xxx.xxx.xxx --dport
25
> -j DNAT --to 192.168.0.5:25
>
> # iptables -t nat -A PREROUTING -p tcp -i eth0 -d xxx.xxx.xxx.xxx --dport
> 110 -j DNAT --to 192.168.0.5:110
>
> # iptables -A FORWARD -p tcp -i eth0 -d 192.168.0.5 --dport 25 -j ACCEPT
> # iptables -A FORWARD -p tcp -i eth0 -d 192.168.0.5 --dport 110 -j ACCEPT
>
> # iptables-save > /etc/sysconfig/iptables
>
>
> When i used nmap to determine if ports 25 and 110 are open, it says:
>
> 25/tcp     filtered    smtp
> 110/tcp    filtered    pop-3
>
> and when i try telnetting its valid ip
>
> #telnet xxx.xxx.xxx.xxx 25
>
>
> it says "trying...." and can't connect at all...
>
> How's this? Did I missed something here? Please Help!!!
>
>
> Oliver
>
>
>
>
>