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I'm running cPanel/WHM with ConfigServer Firewall (csf).

I want to forward port 8080 on my webserver to an internal server with an IP of lets say thats running a webserver on port 80. How can I do this?

My WAN ip is running on eth0 The internal server is connected using the eth1 interface.

What would be the appropriate IPtables cmd to do this?

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migrated from Jul 12 '11 at 4:06

This question came from our site for professional and enthusiast programmers.

Dup of:… – Ward Jul 12 '11 at 5:07

2 Answers 2

Something like this should work

sudo /sbin/iptables -t nat -I PREROUTING -i eth0 -p tcp -m tcp --dport 8080 -j DNAT --to-destination

If you haven't already done so you may need to enable IP forwarding too

/sbin/sysctl -w net.ipv4.ip_forward=1

and to make it permanent edit /etc/sysctl.conf and set

net.ipv4.ip_forward = 1


As the policy on your FORWARD chain is DROP you will need to allow packets through. I don't think your current FORWARD rule is doing anything helpful so delete it.

Enable packets sent to FORWARD from eth0:8080 to be sent to

/sbin/iptables -I FORWARD  -p tcp -m tcp  -d --destination-port 80 -j ACCEPT

Allow packets to go the other way too

/sbin/iptables -I FORWARD -i eth1 -p tcp -m tcp -j ACCEPT

You mat want to restrict the latter further.

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Will that actually working considering the ip is on eth1? – William Balkcom Jul 11 '11 at 22:37
Didn't seem to work. – William Balkcom Jul 12 '11 at 0:00
@WilliamBalkcom: yes, you are routing packets from eth0:8080 -> or at leasts that's what you requests. This works on a test system I have. Check that you have something listening on Is running a firewall and is it allowing connections on port 80 ? Check that your FORWARD chain is allowing packets. – Iain Jul 12 '11 at 6:55
I have a webserver listening on, it is allowing all connections. The connection to is established through eth1 and eth1 is configured like this: And actually the IP is, just using as an example. – William Balkcom Jul 12 '11 at 7:11
@WilliamBalkcom: please post the (suitably redacted) output of iptables -l -v -n and iptables -t nat -L -v -n – Iain Jul 12 '11 at 8:29

Something like:

iptables -A PREROUTING -t nat -i eth1 -p tcp \ 
  --dport 8888 -j DNAT --to

Sends forwards the requests on port 8888.

iptables -A INPUT -p tcp -m state --state NEW --dport 8888 -i eth1 -j ACCEPT

Allows incoming connections ton port 8888.

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