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AC87U - Port Forwarding, Is a DMZ Required

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BasicBlue

Occasional Visitor
Good Day,

I hop everyone is enjoying their new year so far. I am having an issue with my RT AC87U Router. Specifically, the port forwarding feature. I have followed the directions to enable port forwarding on the router so I can access my LAN Minecraft Server from the WAN. It seems like a simple process but after enabling the feature and specifying the ports to forward ( tcp/udp 19132:19133) and IP address of the server 192.168.0.88, I find that it will not work.

I cannot ping the WAN IP or the internal LAN server unless I put the router in a DMZ. Is this the normal protocol? I think not because on my old router a DMZ was not required. The DMZ limits me to exposing only one of my LAN machines and prevents other features such as OpenVPN or a www server from being run.

I would like to forward the ports without implementing a DMZ, any suggestions why this is happening, or if a DMZ is indeed required....? I am not a pro but weould happly try to use some network tools to diagnose this problem if anyone know the best approach as ping alone is not sufficient.

Thank you in advance!
 
You are forwarding the ports for the TCP and UDP protocols only. "ping" uses ICMP. Therefore when someone on the internet pings your public IP address they are pinging your router's WAN interface, not your LAN server. Whether your router responds to pings is dependent on whether you've enabled that option in the GUI.
 
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You are forwarding the ports for the TCP and UDP protocols only. "ping" uses ICMP. Therefore when someone on the internet pings your public IP address they are pinging your router's WAN interface, not your LAN server. Whether your router responds to pings is dependent on whether you've enabled that option in the GUI.
Ok, well I can ping the WAN from a DMZ but the real issue is not ping but why port forwarding will not work unless I enable a DMZ.
 
Then I don't see why it wouldn't work. Post a screenshot of the router's System Log - Port Forwarding page.
 

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It won't work even with modem in bridge mode if your WAN IP address is CG-NAT type. Can you confirm your WAN has a public IP address?
 
You said in post #1 that your were forwarding two ports (19132 and 19133) but I only see one in your screenshot. From what I've read Minecraft only uses one port anyway and that's TCP, not UDP so it should work regardless.

As this works when you put the server in the DMZ I suggest that you do that. Then once someone's connected to it confirm what ports it's actually using by looking at System Log - Active Connections.

P.S. I'm assuming that you're testing this from the internet and not from your internal LAN.
 
You said in post #1 that your were forwarding two ports (19132 and 19133) but I only see one in your screenshot. From what I've read Minecraft only uses one port anyway and that's TCP, not UDP so it should work regardless.

As this works when you put the server in the DMZ I suggest that you do that. Then once someone's connected to it confirm what ports it's actually using by looking at System Log - Active Connections.

P.S. I'm assuming that you're testing this from the internet and not from your internal LAN.
You are correct. I only need one port so I removed the second to make troubleshooting easier. I will enable the DMZ and then connect and check the system logs as you suggested. I am testing this from the internet.

I cannot hit the server at all. At most all I can do is ping the WAN when in DMZ and if DMZ is off I can no longer ping the WAN. I cannot hit the port at all. I have attached the report from a external port checking site and the setup of my port forwarding in case it is something silly that I missed.
 

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That looks fine.
At most all I can do is ping the WAN when in DMZ and if DMZ is off I can no longer ping the WAN.
That's because DMZ also forwards ICMP, so your server is responding to the pings. When not using DMZ your router would have to respond. In which case you need to enable that option in the GUI (Firewall - General).
 
That looks fine.

That's because DMZ also forwards ICMP, so your server is responding to the pings. When not using DMZ your router would have to respond. In which case you need to enable that option in the GUI (Firewall - General).
Right, that makes sense and I realize that was what you were trying to tell me in the first reply. So... is it time to do a hard reset of the router and try again? I am at a loss.

Thank you
 
I went back and reviewed everything. Saw no errors and decided to do hard reset to factory and enter my configurations settings again.

It worked. I have port-forwarding working with no DMZ.

Thank you for all the tips!
 

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