Re: port forwarding problem

[Ian McBeth <imcbeth@telus.net>]

Hello.....

I think you must have the SNAT in there as well


-A PREROUTING -p tcp -m tcp -d (external IP) -i eth1 --dport 25 -j DNAT
--to-destination 192.168.0.2:25
-A POSTROUTING -p tcp -m tcp -s 192.168.0.2 -o eth1 -j SNAT --to-source
62.194.25.2:25


-A FORWARD -p tcp -m tcp -d 192.168.0.2 -i eth1 -o eth0 --dport 25

let me know if this helps

Ian

On Tue, 2003-01-28 at 01:14, oarojo@intermediacorp.com wrote:
> hello guys!!! Can someone help me on my problem regarding iptables???
> 
> This has been my problem a month now.. I'm running a redhat 7.3
firewall
> server with two NICs; eth0 facing the internal network (192.168.0.x)
and
> eth1 facing the internet (external network). Now I wish to forward all
> traffic on eth1, port 25 to another to my mail server (say,
192.168.0.2). I
> did something like:
> 
> iptables -t nat -A POSTROUTING -s 192.168.0.0/24 -j MASQUERADE
> iptables -A FORWARD -p tcp --dport 25 -d 192.168.0.2 -j ACCEPT
> iptables -A PREROUTING -t nat -p tcp --dport 25 -d x.x.x.x -j DNAT
>  --to 192.168.0.2
> 
> Now when i used to test SMTP connection thru telnetting from another
> server... say:
> 
> #telnet xxx.xxx.xxx.xxx 25
> 
> It just stucked in there doesn't continue...
> 
> using nmap on my firewall:
> 
> #nmap xxx.xxx.xxx.xxx -p 25
> 
> it says that port 25 is filtered...
> 
> 
> Is there anything wrong with my iptable rules? I would really
appreciate if
> you can send me your help... thanks!
> 
> 
> Oliver
> 
> 
>