Year after year I have been the one to host a minecraft server for a few weeks when the new minecraft update comes so me and my buddies can have some nostalgia.

Every year I set up the server. In my router settings I set the port and double check the if the server's internal ip is still good. and done. Then I give my friends my external ip. And everything works fine.

But this year I can't figure out why. None of them can join. Everything is the same. The router and it's settings, the pc I run the server on. I'm the only one who can join the server and only with it's internal IP. But not with external one.

I just can't figure it out. I looked around for posts on the subject but did not manage the solve the problem.

What I have tried so far:

  • Disabling the Firewall
  • Resetting the Router
  • Checking if the port forwarded internal ip is the right one

Please help!

  • Here are my first ideas on further troubleshooting: Is the external IP still the right one? Did something change with your internet provider so they don't give you a static IP anymore? Did you change your router settings to a "guest" network or something similar that doesn't allow in-network communication?
    – Plagiatus
    Feb 8, 2023 at 12:54
  • have you consulted your ISP about forwarding recently? most ISP have been blocking that option in their domestic service
    – TonyCR1975
    Feb 9, 2023 at 11:09

1 Answer 1


You may have been put behind CG-NAT (Carrier Grade NAT) wich would explain your problem very well. The short answer for why is that we are running out of IPv4 addresses. If you want the long answer for why, then you can read more about it here:

You should be able to test this by having your friends connect to you with your IPv6 address instead, if it is activated. If that works, then you're surely behind CG-NAT. Most ISP's should have IPv6 activated by now. Also, if you have a old router, IPv6 might not be activated by default or even worse, not be supported at all.

If above works, then you don't really need to do anything as long as you play modern games that support IPv6.

But contact your ISP and ask them if they have done something, if you are behind CG-NAT. If it turns out that this is the case, then you can ask them for a public IPv4 address wich is the "normal" way. Some ISP's let you change back for free while some charge you for it. Some ISP's don't even have that service.

Another solution is to set up a virtual LAN. There are a couple of different softwares that can be used for this. GameRanger is a popular one. Hamachi used to be very popular, but don't seem to be so anymore.

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