Port forwarding to Minecraft server fails on RT-AC68U

[Rasmus Faber]

Hi,

I have installed a Minecraft server for my son on a Ubuntu server. It works as it should when connecting from inside the Lan.

To allow his friends to connect it, I have tried to add a simple port forwarding rule forwarding TCP and UDP from the relevant port to the server, but this does not work. When trying to connect to the external IP, Minecraft reports java.net.ConnectException: Connection timed out: no further information:

I have other port forwarding rules configured for SSH and other services and they work as they should.

www.canyouseeme.org reports that the port is open.

If I run netstat while trying to connect through the external IP, it shows a connection in SYN_RECV state, so it looks like something might be blocking some packages.

If I try to port forward to another (Windows) machine running Minecraft server it still fails, so I strongly suspect something with the router port forwarding.

The router is an Asus AC-N66U running Asuswrt-merlin 378.56_0.

Do anyone have any ideas what could be going wrong? Have anyone successfully port forwarded Minecraft through an Asus router? Any logs I can look into (the general log does not show anything interesting)?

Cheers,
Rasmus.

 

[tim]

I run a Minecraft server for my son, here is what I did:

1) Give the server a fixed IP address
2) Forward port 25565 TCP/UDP to the server IP address on the router
3) Allow incoming connections for port 25565 on the server machine.

Hope that helps.

EDIT: I don't know anything about creating firewall rules under Linux. Best find someone who has the knowledge.

 

[scottts]

Hi,

I have installed a Minecraft server for my son on a Ubuntu server. It works as it should when connecting from inside the Lan.

To allow his friends to connect it, I have tried to add a simple port forwarding rule forwarding TCP and UDP from the relevant port to the server, but this does not work. When trying to connect to the external IP, Minecraft reports java.net.ConnectException: Connection timed out: no further information:

I have other port forwarding rules configured for SSH and other services and they work as they should.

www.canyouseeme.org reports that the port is open.

If I run netstat while trying to connect through the external IP, it shows a connection in SYN_RECV state, so it looks like something might be blocking some packages.

If I try to port forward to another (Windows) machine running Minecraft server it still fails, so I strongly suspect something with the router port forwarding.

The router is an Asus AC-N66U running Asuswrt-merlin 378.56_0.

Do anyone have any ideas what could be going wrong? Have anyone successfully port forwarded Minecraft through an Asus router? Any logs I can look into (the general log does not show anything interesting)?

Cheers,
Rasmus.

You'll get that same message if there's a firewall on either your server or the computer the person trying to log in with and it is not set to allow java to connect. Happens to me sometimes on Windows machines when a java update occurs.

 

[Puppa]

I'm puzzled by your initial question so I thought I'd point out a few things.
1) Subject says the problem is on a RT-AC68U but in the body, you say you're using an RT-N66U. Which is it?
2) You mention you're running Merlin's 378.56_0 build. If you're using an RT-N66U, the latest stable build is 378.55,
3) If this question is about Merlin firmware, you should be posting under the ASUS-WRT Merlin subforum.

 

[Rasmus Faber]

Turns out that the server was actually reachable from outside the network.

I still find it strange that the router seems to corrupt the connection when I try to use the external address from inside, but I can easily avoid that.

Sorry about the confusion about the versions. I have both routers, but it is the RT-AC68U that connects to the outside and seems to be causing the problem. The problem doesn't seem to be something that would be caused by the Merlin modifications, but of course I ought to see how the vanilla version behaves.

Anyway: thanks for the assistance.