iptables to forward port and make sure only access internet from vpn...help?

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Regular Contributor
I have a ac68u with asusmerlin's 384.13.

router ( ..... nas (
..... laptop (

I can talk all the way up and down the network and dnsmaq works great too. I am having trouble getting iptables setup to forward incoming port 85 to Machine ( and to make sure that Machine is only able to communicate to the internet via tun11.

on the router:
  iptables -I FORWARD -i tun11 -p udp -d --dport 85 -j ACCEPT
  iptables -I FORWARD -i tun11 -p tcp -d --dport 85 -j ACCEPT
  iptables -t nat -I PREROUTING -i tun11 -p udp --dport 85 -j DNAT --to-destination
  iptables -t nat -I PREROUTING -i tun11 -p tcp --dport 85 -j DNAT --to-destination

  iptables -t nat -A POSTROUTING -s -o tun11 -j ACCEPT
  iptables -t nat -A POSTROUTING -s -o <everythng> -j DROP
I haven't figured out with the <everything> is yet...

But it is not working. I need some fresh eyes. Please help
Last edited:


Regular Contributor
An interesting thing here.... On the Advanced_OpenVPNClient_Content.asp page I can add to forward to tun11 and tracert works. However when I add to forward to tun11 and run traceroute it goes through the wan and not tun11.

Not sure if this helps any but my wan-start includes;
ifconfig br0:net172 netmask broadcast up


Regular Contributor
ebtables might work. I would recommend setting up a guest network which has only Internet access, no LAN. Then, do ebtables -L to see the rules in effect. Then duplicate these rules to govern your vpn connection.


Regular Contributor
I have been looking to find where the iptables, ebtables are for tun11 are now. But I can't seem to find them. I was going to try and duplicate those.

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