I'm trying to setup a minecraft server: server is on ubuntu comp, client on windows comp.

1) On my.public.ip.adress I can't play: java.net.connectException: connection refused: no further information:

2) On server's IP) it works, can play on LAN

So problem must be port forwarding:

3) tried the 25565 but also tried with another one.

4) on router i've set: NAT/virtualServers/add ----> 25565,25565,TCP/UDP,25565,25565, also NAT/Port Triggering ----> 25565,25565,TPC/UDP,25565,25565.

5) at canyouseeme.org it CAN see my service at, it's visible.

6) at server's config file set: online mode:true/false both don't work

7) server's logs don't show any attempt of connection, problem must be on the router side.

halp! U_U

EDIT: window's firewall desactivated. still don't work

  • 1
    Is the server on your local network? Many routers don't allow local loop back. Is really your IP address?
    – TZHX
    Aug 27, 2014 at 6:55
  • @TZHX I think it's just a mask.
    – Kaz Wolfe
    Aug 27, 2014 at 7:06
  • is my public IP, not THAT one but never say yor IP :P server is on my local network. If many servers don't allow local loopback I can't test it :(
    – Javier
    Aug 27, 2014 at 7:28
  • 1
    Test it from a different connection. Connect to your server from your own network on a local IP address (usually 192.168.X.X). Other people connect using external IP. It's the router that stops local loop back (for valid reasons), not the server.
    – TZHX
    Aug 27, 2014 at 8:16
  • I'm flagging this question as off-topic because it appears to be a general networking problem, not one specific to games.
    – pppery
    Sep 8, 2019 at 0:14

3 Answers 3


Routers, as a general rule, do not allow local loop-back of connections, or martian packets as they are sometimes known. This is for valid network security reasons and the number of routers that make this optional are in the minority, and even if yours is one of them enabling it just to play a game is something I would strongly recommend against.

Connect to your server from the local network IP address (typically along the lines of 192.168.X.X). Have your friends connect using the public IP address.

  • You might be right, @TZHX also suggested it and found same case on another forum. I'll need to wait some days to test it :D
    – Javier
    Aug 27, 2014 at 10:55
  • 1
    @Javier Yeh, that TZHX seems to know what he's talking about.
    – TZHX
    Aug 27, 2014 at 15:16

It could be your ISP (Internet Service Provider). Sometimes your ISP will block certain ports for some reason or another. A very common one the Minecraft port (25565). If this is your problem then you need to contact your ISP and see if you can get that port unblocked for you.

If that's not the case then it could be a combination of things. One, being your ISP blocking ports, and another such as the IP you are using. The 192.168.x.x IPs are generally internal IPs that your computer posses. The reason why when other people have this problem and only they can play is because they are connecting to their internal IP.

Also, make sure in your server.properties file that you leave the sever ip section blank. That also maybe the case in your situation.

  • server.properties/server ip now blank. Tried port 7777, again: working on LAN, not working thru public IP Must be the router's config 100% sure
    – Javier
    Aug 27, 2014 at 7:39
  • Or your ISP, thats usually the case
    – benimen16
    Aug 29, 2014 at 3:02
  • If you really need to, use port 80 or 443 (HTTP/HTTPS). Those are almost never blocked XD. Other ports you can use are 21 (FTP), 22 (SSH/SFTP).
    – RetroCraft
    Feb 11, 2015 at 1:41

I'm pretty sure you're trying to connect locally with your external IP address: it will never work on some networks.

  • If you use your external IP, it will still work, you just have to set it up properly.
    – Frank
    Aug 28, 2014 at 20:13
  • 1
    What exactly do you mean by "setup properly" ?
    – kiwixz
    Aug 28, 2014 at 20:38
  • Port forwarding, obviously. I'm disputing that it will never work; actually it will always work, once you do it right. All it takes is some proper NAT knowledge.
    – Frank
    Aug 28, 2014 at 21:06
  • For me, even with correct portforwarding, that won't work locally. My IP is redirected to the panel of my box.
    – kiwixz
    Aug 28, 2014 at 21:13
  • Which means it's not correct port forwarding. An external IP is exactly that; it will leave your network, and enter again just like other data. For ANY external data to work, that has to be set up properly.
    – Frank
    Aug 28, 2014 at 21:17

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