ufw: how to forward single port to another port on different interface

Question

I have two interfaces eth0 (192.168.1.2) and eth1 (192.168.3.2).

I receive data from 8080 at eth0. I want to forward it to eth1 port 80.

I'm using UFW, because i don't understand iptables and how to add it at the beggining of /etc/ufw/before.rules.

I've already edited DEFAULT_FORWARD_POLICY="ACCEPT" on /etc/default/ufw and already edited net.ipv4.ip_forward=1 on /etc/ufw/sysctl.conf

Solution

DNAT may suffice:

# iptables -t nat -A PREROUTING -i eth0 -p tcp -d 192.168.1.2 --dport 8080 -j DNAT --to-destination 192.168.3.2:80

The UFW before.rules file from some altagoobingleduckgoing looks like it uses the iptables-save format, so thus may contain something along the lines of:

*nat
:PREROUTING ACCEPT [0:0]
-A PREROUTING -i eth0 -p tcp -d 192.168.1.2 --dport 8080 -j DNAT --to-destination 192.168.3.2:80
COMMIT

Comments

[davidbaumann]

So there's a service running on eth1 port 80, and you want it to accept connections on eth0 port 8080?

[sergius]

people connect to eth0 8080, but the server is at eth1 80. I want to redirect or forward the data so they can see my server.

[davidbaumann]

Imho, if you are in control of that service, it should be better to configure the service, instead of doing this workaround...

[sergius]

i can't change this scenario, need to solve it with this configuration. Thanks, David =)