Northbound/Assets/Scripts/QUICK_FIX_GUIDE.md

Quick Fix Guide for "Failed to Connect to Server"

Your Issue: Teammate sees "CONNECTED" but can't join

This is likely a Firewall issue even with port forwarding.

Immediate Actions (Try in Order)

1. Disable Windows Firewall Temporarily (Test Only)

Windows Security → Firewall & network protection → Private network → Microsoft Defender Firewall: OFF
Public network → Microsoft Defender Firewall: OFF

Then test connection. If it works, re-enable and create specific rule for Unity.

2. Add Unity Exclusion to Firewall

Run these commands as Administrator in PowerShell/CMD:

# Allow Unity Editor
netsh advfirewall firewall add rule name="Unity Editor" dir=in action=allow program="%ProgramFiles%\Unity\Hub\Editor\*\Unity.exe" enable=yes

# Allow your built executable (replace path)
netsh advfirewall firewall add rule name="Northbound Game" dir=in action=allow program="D:\Northbound\Build\Northbound.exe" enable=yes profile=any

# Allow port 7777
netsh advfirewall firewall add rule name="Unity Port 7777" dir=in action=allow protocol=TCP localport=7777 enable=yes profile=any

3. Verify Port Forwarding is Working

Go to: https://www.yougetsignal.com/tools/open-ports/

• Enter your PUBLIC IP (what you give to teammate)
• Enter port 7777
• Click "Check Port"

Expected: "Port 7777 is open on [YOUR PUBLIC IP]" If closed: Port forwarding is incorrect

4. Add Debug Scripts to Scene

Add these components to your NetworkManager GameObject:

1. ConnectionDiagnostics - Checks for configuration issues
2. NetworkDebugger - Shows detailed connection logs
3. NetworkConnectionFixer - Fixes common timeout issues

Right-click each and select "Run Diagnostics" or "Fix All Known Issues"

What to Check in Console

Host Should See:

✓ [NetworkConnectionFixer] Network fixes applied
✓ [ConnectionDiagnostics] System Healthy
✓ [NetworkDebugger] Server Started Successfully
✓ [NetworkDebugger] Listening on: 0.0.0.0:7777
✓ [NetworkDebugger] Client Connected: [ID]
✓ [ConnectionHandler] 클라이언트 [ID] 승인됨. 수동 스폰으로 대기.

Client Should See:

✓ [NetworkConnectionFixer] Network fixes applied
✓ [ConnectionDiagnostics] System Healthy
✓ [NetworkDebugger] Connection Approval Request from Client [ID]
✓ [NetworkDebugger] Approval Response: Approved: true

If Still Not Working

Check These Settings:

On NetworkManager GameObject:

• Player Prefab assigned
• Network Prefabs list populated
• Transport component = Unity Transport (UTP)

On Unity Transport Component:

• ConnectionData.Port = 7777 (or your port)
• ConnectionData.Address = 0.0.0.0 for Host
• Connect Timeout MS = 15000
• Max Connect Attempts = 10

In NetworkManager Inspector (Network Config):

• Connection Approval = checked
• Enable Scene Management = checked

Common Mistakes

❌ Using 127.0.0.1 or 192.168.x.x for teammate ✓ Use your PUBLIC IP for teammate

❌ Firewall blocking Unity ✓ Add exception for Unity and your game

❌ Port not actually forwarded ✓ Verify with online port checker

❌ Wrong transport address on host ✓ Host should use 0.0.0.0, client uses YOUR public IP

❌ Player prefab missing NetworkObject ✓ Ensure player prefab has NetworkObject component

Quick Test Sequence

1. Test Local:

   • Start Host (connect to 127.0.0.1 from same instance)
   • If this fails: Project setup issue

2. Test LAN:

   • Use 192.168.x.x (local network IP)
   • If this fails: Network/Firewall issue

3. Test Internet:

   • Use public IP
   • If this fails: Port forwarding issue

Console Commands for Diagnostics

Add this to a MonoBehaviour:

[ContextMenu("Check Everything")]
void CheckEverything()
{
    Debug.Log("IsServer: " + NetworkManager.Singleton.IsServer);
    Debug.Log("IsClient: " + NetworkManager.Singleton.IsClient);
    Debug.Log("ConnectedClients: " + NetworkManager.Singleton.ConnectedClients.Count);
    Debug.Log("Local IP: " + NetworkUtility.GetLocalIPv4());
}

Last Resort Solutions

1. Use VPN/Hamachi

   • Creates virtual LAN between you and teammate
   • No port forwarding needed
   • Both connect to VPN IP

2. Use Unity Relay

   • Built into Unity Netcode
   • Bypasses NAT/Firewall completely
   • Requires Unity Services account

3. Host on Cloud Server

   • AWS/Azure/Google Cloud
   • Static IP, no port forwarding
   • More reliable

Share These for Help

If still broken, share:

1. Full Console log (Host and Client)
2. Screenshot: NetworkManager inspector
3. Screenshot: Unity Transport settings
4. Port checker result screenshot
5. Windows Firewall rules screenshot

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Most likely issue: Windows Firewall is blocking even with port forwarding. Fix: Run firewall commands in step 2.