-1

Im trying to redirect the TCP connections a port multiple times to another ports, i tried this before but didn't work:

iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 60000 -j REDIRECT --to-port 60001
iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 60001 -j REDIRECT --to-port 60002

I'm trying to get port 6000 to redirect tcp connections to port 60001, then port 60001 will redirect the connection to port 60002.

X -> Y -> Z

what can I do?

  • I know there must be a reason, but can you tell why don't you redirect 6000 to 6002 directly? And maybe something about the use case? – Eduardo Trápani Jun 3 at 4:41
  • 1
    So for the 3rd time I write again the same comment: On Linux you cannot NAT (redirect) with conntrack a flow that is already redirected with conntrack. I would write an answer to tell "no" (and give the technical reason)but I'm not sure that will help. – A.B Jun 3 at 5:08
  • 1
  • 3
    Please do not blank your questions out when solved. – ceejayoz Jun 4 at 15:50
  • 1
    Please don't make more work for other people by vandalizing your posts. By posting on the Stack Exchange (SE) network, you've granted a non-revocable right, under the CC BY-SA 4.0 license for SE to distribute that content. By SE policy, any vandalism will be reverted. If you want to know more about deleting a post, consider taking a look at: How does deleting work? – Glorfindel Jun 12 at 19:30
2

Your mitigate step needs to forward the connection to your game server, you cannot do this with IPTables.

| improve this answer | |
  • So, what tool i can use to do that? – Gabriel Jun 3 at 9:17
  • I don't know know of any tool for that, I just know the principle what should be done. – Tero Kilkanen Jun 3 at 15:13
0

You cannot match the same packet twice with different DNAT rules. But you can make the whole structure more complicated and thus more flexible.

You can create a chain for each destination port you want to handle:

iptables -t nat -N port60000
iptables -t nat -N port60001

If you match a packet you do not send it to the DNAT target but to the respective chain:

iptables -t nat -A PREROUTING -p tcp --dport 60000 -j port60000
iptables -t nat -A PREROUTING -p tcp --dport 60001 -j port60001

In the original state the chains do the same as the old commands, just a bit more slowly...

iptables -t nat -A port60000 -p tcp -j DNAT --to-destination :60001
iptables -t nat -A port60001 -p tcp -j DNAT --to-destination :60002

If you want to change 60000 => 60001 to 60000 => 60002 then you can change the content of port60000:

iptables -t nat -A port60000 -p tcp -j port60001
iptables -t nat -D port60000 -p tcp -j DNAT --to-destination :60001

But that this is possible does not mean that this is better than recreating the rules after a change.

| improve this answer | |

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.