Minecraft Getsockopt Error – Causes & How to Fix It

TL;DR: The getsockopt error in Minecraft is a network connectivity problem, not a mod or installation issue. Start by allowing Java/Minecraft through your firewall, test again with the firewall temporarily off, then switch your DNS to Google (8.8.8.8 / 8.8.4.4). If you’re joining a friend’s server, make sure they’ve port-forwarded 25565 correctly.

What is the getsockopt error?

getsockopt is a low-level networking call. When Minecraft (the client) can’t complete a connection to a server or LAN world, Windows reports a failure from that call and the game surfaces it as the getsockopt error.
Key points:

• It typically appears when attempting to join an online/LAN server.
• It’s not caused by a specific mod or a broken game install.
• Root causes are almost always firewall, DNS, or router/server configuration.

Quick checks before you dive in

• Confirm the server is online and you’re using the right IP/port.
• Test your internet on a browser or another online game.
• If multiple players can’t join the same server, it’s likely server-side.

Fix 1 – Allow Java & Minecraft through Windows Firewall

1. Press Start and open Windows Defender Firewall.
2. Click Allow an app or feature through Windows Defender Firewall → Change settings.
3. Find and check Java(TM) Platform SE binary (a.k.a. javaw.exe) for both Private and Public.
4. Also check Minecraft Launcher and Minecraft if they appear.
5. If Minecraft isn’t listed, click Allow another app… → Browse, and add:
   • MinecraftLauncher.exe (usually under C:\Program Files (x86)\Minecraft Launcher\)
   • javaw.exe (e.g., C:\Program Files\Java\…\bin\javaw.exe)
6. Click OK and try joining the server again.

Why this works: If the firewall blocks Java/Minecraft, the TCP handshake can’t complete, and Windows reports a getsockopt failure.

Fix 2 – Temporarily turn the firewall off (test only)

If whitelisting didn’t help, do a quick test:

1. In Windows Defender Firewall, select Turn Windows Defender Firewall on or off.
2. Turn it Off for Domain, Private, and Public networks.
3. Try joining the server.

Important: Turn the firewall back on immediately after testing. If the connection works only with the firewall off, you need to re-check your allowed apps or create a custom inbound/outbound rule for Java/Minecraft.

Fix 3 – Change DNS to Google DNS

Sometimes DNS resolution (turning a domain into an IP) is slow or failing.

1. Open Control Panel → Network and Internet → Network and Sharing Center.
2. Click Change adapter settings (left sidebar).
3. Right-click your active connection (Wi-Fi or Ethernet) → Properties.
4. Select Internet Protocol Version 4 (TCP/IPv4) → Properties.
5. Choose Use the following DNS server addresses and enter:
   • Preferred DNS: 8.8.8.8
   • Alternate DNS: 8.8.4.4
6. (Optional) For IPv6, use 2001:4860:4860::8888 and 2001:4860:4860::8844.
7. Click OK, then open Command Prompt (Admin) and run: ipconfig /flushdns
8. Restart your PC and try again.

Why this works: Using reliable public DNS reduces lookup failures/timeouts that can trigger socket errors.

Fix 4 – If you’re joining a friend’s/self-hosted server

If the error only occurs when connecting to a specific server you or a friend host, the issue may be on the server side:

• Port forwarding: Forward TCP 25565 on the router to the server machine’s local IP.
• Static LAN IP: Give the server PC a stable local IP so the port forward doesn’t break after reboots.
• Firewall on the server: Allow inbound TCP 25565 for Java/Minecraft.
• Public IP changes: If using a residential ISP, the public IP can change; consider a dynamic DNS service.
• Double NAT/Carrier-grade NAT: If the ISP uses CGNAT, standard port forwarding may not work use a hosted server or tunneling solution.

Optional advanced steps (use with care)

If the above fixes don’t help, these Windows networking resets can clear stale sockets and policies:

1. Open Command Prompt (Admin) and run: netsh winsock reset ipconfig /flushdns
2. Restart your PC and test again.

Note: Only run broader resets (e.g., netsh int ip reset) if you understand the impact those can wipe custom network configs.

When to escalate

• Multiple players cannot join the same server: it’s almost certainly server-side.
• You can join other servers, but not one specific server: ask the server owner to re-check port forwarding and firewall.
• Still stuck? Contact Mojang Support and/or file a bug report with your launcher logs and a description of what you already tried.

FAQs

Is the getsockopt error caused by mods?
No. It’s a network problem. Mods rarely cause it unless they change how you connect (e.g., proxies), but the error itself isn’t a mod crash.

Does reinstalling Minecraft fix this?
Usually no. Reinstalling won’t change firewall rules, DNS, or router settings the common sources of this error.

What port does Minecraft Java use?
Default is TCP 25565. If a server uses a custom port, include it in the address (e.g., example.com:25570).

Summary

• Start with Firewall allowlist for Java/Minecraft → test.
• If needed, temporarily disable firewall to confirm it’s the cause (then re-enable).
• Switch to Google DNS and flush DNS.
• For private servers, verify port forwarding 25565 and inbound firewall rules.
• Use winsock/DNS flush for stubborn cases.