Port forwarding not working - tcpdump receives packets

Installing and Using OpenWrt Network and Wireless Configuration
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Hi, I am trying to set up port forwarding for UDP 6000-6009 on my Archer C7 runnning OpenWrt 18.06.2 r7676-cddd7b4c77 / LuCI openwrt-18.06 branch. However, when testing using https://www.ipfingerprints.com/portscan.php, the ports are shown as closed (I've selected UDP scan). In terms of troubleshooting, tcpdump -pnvvi eth0.2 port 6000 does show the received packets, so it seems as though my ISP isn't blocking it.

I've set up the port forwards via the GUI (Network > Firewall > Port Forwards) and am stuck with how to resolve this issue. Any assistance is greatly appreciated.

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Don't trust blindly these internet scanners.
Does it work for you or not?
You can verify that the packet is forwarded by running the tcpdump in the inside interface.

2 Likes
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Also, even if your router receives and forwards the packets correctly, the destination host must also be configured to receive them.

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Good points, I did make sure the internal firewall on the host was off, and used netcat to listen on that port. But I'll give it a try without using the port scanner - could try from a machine outside the network