Direct answer

“getsockopt” or “No further information” usually indicates a low-level connection failure, often before Minecraft completes login. It is not proof that a mod or Java installation is broken.

Identify the failing layer

A closed port test while the server is stopped tells you nothing useful. Do not expose every backend port to “fix” a proxy address.

First checks and evidence

  • Confirm the exact server hostname and TCP port; resolve the hostname and check whether the server process is listening.
  • Test localhost on the host and the LAN IP from another local device before testing the public address.

Admin diagnosis and repair

  1. If local access works but public access fails, inspect router forwarding, host firewall, CGNAT and DNS destination.
  2. If there is a proxy, test its public listener while keeping backends private; correlate the connection attempt with proxy logs.

Verify the fix: A friend outside your LAN should reach the correct Java listener and leave a corresponding entry in the server or proxy log.

References

Use the documentation for the exact software and release you run. These sources support the settings or diagnostic behavior used in this fix.

Was this article helpful?
Help us improve this article

Tell us what is missing, unclear, outdated, or incorrect. You can also suggest something we should add.

What could we improve?
Do not include passwords, server IPs, or other private information.0 / 1000