Mindustry Server Port Forwarding
Open port 6567 (both TCP and UDP) so players can find and connect to your Mindustry server. Covers UFW, firewalld, iptables, and troubleshooting the most common connection issue.
Mindustry Server Port Forwarding
Mindustry uses a single port: 6567, but it must be open on both TCP and UDP. Missing either protocol is the most common reason players get stuck on "Connecting..." indefinitely.
Required Port
| Port | Protocol | Purpose |
|---|---|---|
| 6567 | TCP | Reliable connection (lobby, commands) |
| 6567 | UDP | Real-time game state sync |
Both are required. Forwarding only TCP or only UDP will cause connection failures.
Opening Ports with UFW (Ubuntu/Debian)
sudo ufw allow 6567/tcp
sudo ufw allow 6567/udp
sudo ufw reload
Verify:
sudo ufw status
Both 6567/tcp and 6567/udp should show ALLOW.
Opening Ports with firewalld (CentOS/RHEL/Fedora)
sudo firewall-cmd --permanent --add-port=6567/tcp
sudo firewall-cmd --permanent --add-port=6567/udp
sudo firewall-cmd --reload
Opening Ports with iptables
iptables -A INPUT -p tcp --dport 6567 -j ACCEPT
iptables -A INPUT -p udp --dport 6567 -j ACCEPT
Persist with iptables-save > /etc/iptables/rules.v4.
Running Multiple Servers on One Machine
Each instance needs its own port. Increment by 1:
| Instance | Port |
|---|---|
| Server 1 | 6567 |
| Server 2 | 6568 |
| Server 3 | 6569 |
Change the port from the server console:
config port 6568
Direct Connection for Players
Even if the server doesn't appear in the public browser list, players can connect directly:
- In Mindustry, go to Play → Join Game
- Click Add Server
- Enter your server's IP and port:
YOUR_IP:6567
This works even before your server is indexed in the public list.
Troubleshooting Connection Issues
Players stuck on "Connecting...": The most common cause is UDP 6567 not being forwarded. Make sure you've opened both TCP and UDP explicitly — many firewall tools treat them separately.
Cloud/VPS provider firewall: Providers like AWS, DigitalOcean, Hetzner, and Vultr have a second firewall layer (security groups or cloud firewalls) separate from your OS firewall. Both must allow port 6567 TCP and UDP.
Test from outside:
Use portchecker.io or nmap -sU -p 6567 YOUR_IP from an external machine to confirm the port is reachable.