port forwarding

[boondocks]

I have a Ubuntu system that has 2 network cards.

eth0 with ip address 192.168.1.23

eth1 with ip address 192.168.7.15

I would like do port forwarding such that anything for

192.168.1.23:19320

is forwarded to

192.168.7.15:19340

and it should stay that way after rebooting.

How do you do this?

[Iowan]

iptables comes to mind. ufw/gufw may be another approach to the same thing. (Unfortunately, another area I have yet to learn...)

[stilling]

see this

http://ubuntuforums.org/showthread.php?t=93420


mybe this will help you

[boondocks]

iptables comes to mind. ufw/gufw may be another approach to the same thing. (Unfortunately, another area I have yet to learn...)

Currently, ufw is not enabled on this Ubuntu system and I want to keep it that way.
So, is it possible to use gufw so that:

• The firewall is NOT enabled.
• But this one port is forwarded.

[boondocks]

see this

http://ubuntuforums.org/showthread.php?t=93420


mybe this will help you

I am looking at it.

While I was waiting for responses to this post, I found:
http://shahidz.com/iptables-port-forwarding-on-ubuntu/

Looks more like what I need.
Right?

[stilling]

you can try this i`m not relly sure about it but

sudo iptables -t nat -A PREROUTING -p tcp -i eth0 -d 192.168.1.23 --dport 19340 -j DNAT --to 192.168.7.15:19340
sudo iptables -A FORWARD -p tcp -i eth0 -d 192.168.7.15 --dport 19340 -j ACCEPT

echo 1 > /proc/sys/net/ipv4/ip_forward

test and if that is ok

sudo gedit /etc/sysctl.conf
find net.ipv4.ip_forward = 1 remove the # that is placed in front
and add the 2 lines with iptables in /etc/rc.local before exit 0


hope this helps

[boondocks]

you can try this i`m not relly sure about it but

sudo iptables -t nat -A PREROUTING -p tcp -i eth0 -d 192.168.1.23 --dport 19340 -j DNAT --to 192.168.7.15:19340
sudo iptables -A FORWARD -p tcp -i eth0 -d 192.168.7.15 --dport 19340 -j ACCEPT

echo 1 > /proc/sys/net/ipv4/ip_forward

test and if that is ok

sudo gedit /etc/sysctl.conf
find net.ipv4.ip_forward = 1 remove the # that is placed in front
and add the 2 lines with iptables in /etc/rc.local before exit 0


hope this helps

To confirm - this will ensure that all requests will port forwarded (not just mine), correct?

[stilling]

that forwards from eth0 ip to eth1 ip that port

[boondocks]

I need to do the same thing on another Ubuntu system but instead of eth0 and eth1
we have eth0 and TUN virtual network device

Will the same script work?
(Since your script mentions eth0 but not eth1.)

[stilling]

now you know how to do it the problemis that TUN virtual network device must have a name or a ip something like eth1 .... if you understand