How to portforward with iptables?

Applications IP Networking
1

I currently installed openvpn on CentOS 6 64bit and everything is working fine but I want to portforward a client "user" so they can use that port here is what i thought it might work

iptables -t nat -A PREROUTING -p udp -d SERVERIP --dport 3074 -j DNAT --to-destination 10.8.0.6:3074
2

Takes another line at least: Port Forwarding Using iptables - Linux Tutorials - Fclose.com

3 
iptables -A PREROUTING -t nat -i eth0 -p tcp --dport 80 -j DNAT --to 192.168.1.2:8080

But eht0 is not even on my network.

4

Well, you need to use the right symbols for your machine, and you need a FORWARD ACCEPT rule for the return trip. Port Forwarding Using iptables - Linux Tutorials - Fclose.com

5

This is my current iptables

# Generated by iptables-save v1.4.7 on Wed Feb 20 21:17:31 2013
*mangle
:PREROUTING ACCEPT [37157:2159381]
:INPUT ACCEPT [37133:2156855]
:FORWARD ACCEPT [24:2526]
:OUTPUT ACCEPT [60460:8243106]
:POSTROUTING ACCEPT [60484:8245632]
COMMIT
# Completed on Wed Feb 20 21:17:31 2013
# Generated by iptables-save v1.4.7 on Wed Feb 20 21:17:31 2013
*filter
:INPUT ACCEPT [37133:2156855]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [60460:8243106]
-A FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT 
-A FORWARD -s 10.8.0.0/24 -j ACCEPT 
COMMIT
# Completed on Wed Feb 20 21:17:31 2013
# Generated by iptables-save v1.4.7 on Wed Feb 20 21:17:31 2013
*nat
:PREROUTING ACCEPT [5:210]
:POSTROUTING ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-A PREROUTING -p tcp -m tcp --dport 33891 -j DNAT --to-destination 10.8.0.6:3389 
-A PREROUTING -d 37.0.122.190 -p udp -m udp --dport 3074 -j DNAT --to-destination 10.8.0.6:3074
-A PREROUTING -d 37.0.122.190 -p tcp -m tcp --dport 3074 -j DNAT --to-destination 10.8.0.6:3074 
-A PREROUTING -d 37.0.122.190 -p udp -m udp --dport 1604 -j DNAT --to-destination 10.8.0.10:1604
-A PREROUTING -d 37.0.122.190 -p tcp -m tcp --dport 1604 -j DNAT --to-destination 10.8.0.10:1604
-A POSTROUTING -s 10.8.0.0/24 -j SNAT --to-source 37.0.122.190 
COMMIT
# Completed on Wed Feb 20 21:17:31 2013
6

The example there suggests you need these:

iptables -A FORWARD -p tcp -d 10.8.0.6 --dport 3074 -j ACCEPT
iptables -A FORWARD -p udp -d 10.8.0.6 --dport 3074 -j ACCEPT
7

I tried that too,
and then did
service iptables save
service iptables restart
and still not available.

I am currently using canyouseeme and ping. eu /port-chk/
to check if the ports are opening up.

8

Try to 'telnet host port' through, assuming there is a listener at the target, and read the logs.

9

Alright I will try to telnet host and report back.

---------- Post updated at 07:44 AM ---------- Previous update was at 07:24 AM ----------

[root@RUVPN ~]# telnet 37.0.122.190
Trying 37.0.122.190
telnet: connect to address 37.0.122.190: Connection refused

10

You are forwarding port 23? S/b 'telnet host_or_ip 3074' ?

11

Correct me if i am wrong for the allow in iptables.
iptables -A FORWARD -p tcp -d 10.8.0.6 --dport 23 -j ACCEPT
iptables -A FORWARD -p udp -d 10.8.0.6 --dport 23 -j ACCEPT

12

No, the rule we are working on is 3074 tcp, and telnet can tcp to any port, optionally.

13

14

Now see if iptables on 37.0.122.190 logged a packet reject message.