From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Linux" Subject: Re: portforwarding-HOWTO Date: Tue, 7 Jan 2003 15:06:34 -0700 Sender: netfilter-admin@lists.netfilter.org Message-ID: <024e01c2b699$0b9b64e0$d318b2a1@IBMCMDCTR004> References: <2132.192.168.0.1.1041835837.squirrel@mail.intermediacorp.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: Errors-To: netfilter-admin@lists.netfilter.org List-Help: List-Post: List-Subscribe: , List-Id: List-Unsubscribe: , List-Archive: Content-Type: text/plain; charset="us-ascii" To: oarojo@intermediacorp.com, netfilter@lists.netfilter.org Did you turn on Masquerading? Linux303 ----- Original Message ----- From: To: 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 > > > > >