Re: tcp packets on 25 port FORWARDING

[<peter.gehle@sbgit.com>]

Try this:

LAN_IP=$(ifconfig eth1 | head -n 2 | tail -n 1 | cut -d: -f2 | cut -d" " -f 1)
ipatbles -t nat -A PREROUTING -i *EXT-NIC* -p tcp --dport 25 -j DNAT --to_destination *POSTFIX-IP*
iptables -t nat -A POSTROUTING -o *INT-NIC* -p tcp --dport 25 -j SNAT --to-source $LAN_IP
iptables -A FORWARD -i *EXT-NIC* -m state --state NEW -p tcp -d *POSTFIX-IP* --dport 25 -j ACCEPT

EXT-NIC = your external Network Interface (eth0, eth1...)
INT-NIC = your internal Network Interface (eth1, eth2...) where your Postfix Server is connected to
POSTFIX-IP = The IP of your Postfix Server

That should work.

Mit freundlichen Grufl / Best regards / Meilleures
salutation / Met vriendelijke groet

Peter Gehle
Systemberatung Gehle GmbH
Im Bahler Grund 5

D-49413 Dinklage
Germany

Phone : +49 4443 9796-12
Fax   : +49 4443 9796-29

www.sbgit.com


Original Message       processed by Tobit InfoCenter
Subject: tcp packets on 25 port FORWARDING (12-Mrz-2004 10:50)
From:    stanislav.puffler@seznam.cz
To:      peter.gehle@sbgit.com


Hi there,
I need to forward all tcp packets with port 25 (SMTP) from Internet to machine in my network. My settings (eth0 = internet IP, eth1 = 192.168.200.1 - dmz IP connected to another machine with Postfix, eth2 = 192.168.0.1 - gateway - LAN). Have opened port 25 and setup rule :

iptables -t nat -A PREROUTING -p tcp -dport 25 - i eth0 -j DNAT -to 192.168.200.2:85

iptables -A FORWARD -i eth0 -p tcp -d 192:168.200.2 -dport 25 -m state -state NEW,ESTABLISHED,RELATED -j ACCEPT

But it still doesn't route tcp packets on port 25 to my Postfix computer :o( If I try telnet 192.168.200.2 25 from FW it works, if I try this from Internet, it doesn't work :o( Any ideas ? Thanks a lot.
Stan.


To: stanislav.puffler@seznam.cz
Cc: netfilter@lists.netfilter.org