Server setup issues detected during connection attempts.
Server setup issues detected during connection attempts.
You're facing issues with your local MC server setup. The 1.21.1 version causes a getsockopt error, while the older 1.20 version leads to connection timeouts. You're able to connect locally but not through public IP addresses. Port forwarding is configured for TCP/UDP on port 25565, and Java binaries are allowed via firewall, but Windows Defender Firewall isn't permitting Java traffic. Consider checking the firewall rules again, ensuring Java is whitelisted in Windows Defender, and verifying network settings for your public IP.
The networking gear connecting the server to the internet typically includes routers, modems, and sometimes firewalls or load balancers. Common models are Cisco ASA, Juniper MX series, and Huawei equipment.
You only need TCP. Beyond that, you mentioned localhost and a public IP, but you're missing the LAN connection. So 127.0.0.1 is valid, along with 192.168.x.x or 10.x.x.x, and then your public IP will help determine if it's on the PC, local network, or forwarded traffic.
The public IP isn't functioning for you, yet the issue lies with your friends' setups. You must turn on NAT loopback so you can reach your local public IP within their network.
I obtained your public IP through an online service. Verify it matches what your router displays, since it may only show a private CG-NAT address.