Networking

JunimoServer supports both Steam and GOG clients connecting to the same server. Most setups require no port forwarding.

Connection Methods

Method	For	Port Forwarding	Reliability
Steam SDR	Steam clients	Not required	~99% success
GOG Galaxy	GOG clients	Not required	~50% success
Direct IP	Any client	Required (UDP 24642)	Depends on network

Steam SDR (Recommended)

Steam clients connect through Valve's Steam Datagram Relay network. All traffic routes through Valve's servers, which handles NAT traversal automatically.

How it works:

1. Server logs in anonymously to Steam's GameServer API
2. Valve assigns the server a Steam ID
3. Steam-auth service creates a lobby with this ID
4. Players join the lobby and connect via Valve's relay

GOG Galaxy

GOG clients connect using Galaxy P2P networking. Invite codes start with "G". Works through most NATs without port forwarding, but has lower success rates than Steam SDR.

Direct IP

Disabled by default. Enable via AllowIpConnections in server-settings.json.

WARNING

Direct IP connections don't provide user IDs. Players may lose farmhand ownership if they reconnect from a different IP.

Ports

Port	Protocol	Purpose	Forward Required?
24642	UDP	Steam SDR game port	No (relay handles NAT)
27015	UDP	Steam SDR query port	No (relay handles NAT)
5800	TCP	VNC web interface	Only for remote access
8080	TCP	HTTP API	Only for external tools

Steam SDR uses these ports internally but traffic goes through Valve's relay — no port forwarding required for most setups.

Changing Ports

To change host-side port mappings (for conflicts):

# In .env
VNC_PORT=5801
API_PORT=8081
GAME_PORT=24643
QUERY_PORT=27016

Troubleshooting

Network Diagnostics

The container includes netdebug for troubleshooting:

# Check NAT type
docker compose exec server netdebug nat

# Test latency to GOG servers
docker compose exec server netdebug ping

# Test download speed
docker compose exec server netdebug speed

# Monitor GOG Galaxy traffic
docker compose exec server netdebug gog-ports
docker compose exec server netdebug gog-requests

NAT Types

Result	Description	Connection Quality
Open	Full Cone NAT	All connections work
Moderate	Restricted Cone	Most connections work
Strict	Symmetric NAT	May need relay for some

Players Can't Connect

Basic checks:

1. Server running? docker compose ps
2. Run netdebug nat to check network config

Remote players (different network) usually connect fine.

Same-network players often have issues due to "hairpinning" — traffic going out and coming back to the same network.

Check netdebug nat output:

• Hairpinning: Not supported — same-network connections won't work
• NAT Type: Strict — some connections may fail

Same-Network Workaround

Players on the same network can try:

• Connect from mobile hotspot
• Use a VPN service
• Enable direct IP connections (if acceptable)

Steam Clients Can't Connect

Check server logs for these messages:

GameServer init failed:

[Steam] GameServer.Init() failed

Steamworks SDK may be missing or steam_appid.txt incorrect.

Can't reach Steam:

[Steam] Failed to connect to Steam servers: ...

Check outbound network access and firewall rules for UDP.

SDR not ready:

[Steam] SDR relay status: k_ESteamNetworkingAvailability_Unknown

SDR takes a few seconds to initialize — wait and retry.

GOG Clients Can't Connect

1. Verify invite code starts with "G"
2. Run netdebug nat to check NAT type
3. Try having player connect from different network

Firewall Configuration

If you need to configure firewalls, allow:

For Steam/GOG players (default setup):

• Outbound UDP (any port) — for relay connections
• Outbound TCP 443 — for Steam API

For direct IP connections (if enabled):

• Inbound UDP 24642 — game traffic

For remote VNC access:

• Inbound TCP 5800 — VNC web interface

For external API access:

• Inbound TCP 8080 — REST API