Arma Reforger Port Forwarding Guide: Ports & Server Fix
Configure Arma Reforger port forwarding on ports 2001 & 17777 UDP. Fix SERVER_UNREACHABLE on dedicated servers, set up PC/PS5/Xbox co-op, and bypass CGNAT.
Quick Answer: Arma Reforger Required Ports
To host an Arma Reforger server, forward port 2001 UDP (Game Listen Port) and port 17777 UDP (Steam Server Query Port) to your host PC static IP address. Arma Reforger uses UDP exclusively; do not forward TCP. If your server is visible in the browser but players receive "SERVER_UNREACHABLE", check your server.json publicAddress binding and Windows Defender Firewall. If you are behind DS-Lite or ISP CGNAT, use Proton VPN or PureVPN to establish an open inbound port.
Arma Reforger Port Forwarding Guide: Official Ports, Server Fix & CGNAT Bypass
Setting up an arma reforger port forwarding rule should be the exciting first step toward tactical co-op missions with your squad on Everon or Arland. But nothing kills game night faster than spending two hours configuring a dedicated server or local Combat Ops lobby only for friends on PC, Xbox, or PS5 to see the dreaded "SERVER_UNREACHABLE" error or watch connection attempts timeout endlessly.
Whether you are hosting directly inside the game client, launching a Windows or Linux dedicated server via SteamCMD, coordinating crossplay across PC, PS5, and Xbox, or troubleshooting ISP DS-Lite and CGNAT restrictions, this comprehensive arma reforger port forwarding guide provides the exact port specifications, fixes the server list unreachable bug, and guarantees outside players can connect.
Official Bohemia Interactive Arma Reforger Port Matrix
| Service Function | Default Port | Protocol | Role in Arma Reforger |
|---|---|---|---|
| Game Traffic (Direct Join & Enfusion Net) | 2001 | UDP | Essential for player packet exchange, physics, and gameplay data. |
| Steam Master Server Query (A2S Protocol) | 17777 | UDP | Controls community server browser ping, player counts, and listing discovery. |
| Secondary Scenario / Custom Bind Port | 2002-2005 | UDP | Used if hosting multiple concurrent server instances on the same host IP. |
Arma Reforger Port Calculator & Firewall Rule Generator
If you customized your server.json or are hosting multiple instances, adjust the base game and query ports below. The Windows Defender Firewall script and JSON configuration update instantly:
The primary port outside players connect to when joining your lobby.
The A2S query port that makes your server appear in the community server browser.
# Open Inbound UDP Ports for Arma Reforger Server in Windows Defender Firewall
New-NetFirewallRule -DisplayName "Arma Reforger Game Port (2001 UDP)" -Direction Inbound -LocalPort 2001 -Protocol UDP -Action Allow
New-NetFirewallRule -DisplayName "Arma Reforger Steam Query (17777 UDP)" -Direction Inbound -LocalPort 17777 -Protocol UDP -Action Allow{
"bindAddress": "0.0.0.0",
"bindPort": 2001,
"publicAddress": "YOUR_PUBLIC_IP",
"publicPort": 2001,
"a2s": {
"address": "0.0.0.0",
"port": 17777
},
"game": {
"name": "My Tactical Combat Server",
"password": "",
"scenarioId": "{ECC61978EDCC2D5A}Missions/23_Campaign.conf",
"maxPlayers": 32
}
}What Ports to Forward for Arma Reforger? (Debunking Port 25565)
To host an Arma Reforger dedicated or local co-op server, forward port 2001 UDP (Game Traffic) and port 17777 UDP (Steam Master Server Query). Both ports strictly require the UDP protocol.
Is It Safe to Open Port 25565? Why Isn't Port 25565 Open?
A common question returned by Google search is: "Is it safe to open port 25565?" and "Why isn't port 25565 open?".
Port 25565 is strictly the default port for Minecraft Java Edition. Arma Reforger does not use port 25565 whatsoever. If you set up a router rule for 25565, port checkers will show it closed because no Arma Reforger service listens on it, and your friends will still be unable to connect!
Should I Enable Port Forwarding for Gaming?
If you only play multiplayer games as a client joining public servers, you do not need port forwarding (UPnP handles ephemeral outbound sockets).
However, if you host a dedicated server, co-op scenario, or peer-to-peer lobby, port forwarding is mandatory so outside players can initiate unsolicited inbound handshakes through your router.
Dedicated Server Appears on Server List but Is Unreachable: Fix
The most frustrating bug reported on Reddit r/ArmaReforger (threads like "Dedicated Server appears on server list but is unreachable") occurs when:
- Your server appears in the community server browser with ping and player counts.
- Players can see and even download the scenario mods.
- When clicking "Join", the game pauses for 15 seconds and throws
SERVER_UNREACHABLE.
Why This Happens & How to Fix It
1. The Two-Port Asymmetry: Steam query port 17777 UDP handles the server list ping. If 17777 is open but 2001 UDP (the actual game socket) is blocked by Windows Firewall or router NAT, your server advertises itself successfully, but direct gameplay packets cannot enter!
2. Incorrect bindAddress in server.json: Many server admins enter their public IP into "bindAddress". This causes the Enfusion engine socket to fail because your local network card does not own the public IP! Always set:
"bindAddress": "0.0.0.0"3. NAT Hairpinning (Loopback Failure): If you are playing on the same PC or local Wi-Fi where the server is hosted, attempting to join via the server browser using your Public IP will fail if your home router does not support NAT Loopback (Hairpinning). Join via Direct Connect: 127.0.0.1:2001 (or your LAN IP 192.168.x.x:2001) while outside friends join via your Public IP!
Arma Reforger Port Forwarding PC, PS5 & Xbox: Crossplay Rules
Arma Reforger supports full crossplay between PC and consoles. However, consoles enforce strict NAT type matching rules:
Requires forwarding ports 2001 UDP and 17777 UDP in your router and allowing them through Windows Defender Firewall. Check our interactive generator above for one-click setup.
Requires NAT Type 2 (Moderate) or NAT Type 1 (Open). If you host co-op from PlayStation, ensure PlayStation Network UDP ports 3478-3480 and game port 2001 UDP are mapped.
Requires an Open NAT Type. Xbox uses port 3074 UDP for Xbox Live matchmaking alongside Reforger's 2001 UDP. Strict NAT will disconnect crossplay sessions.
How to Set Up Arma Reforger Port Forwarding: 4 Steps
1Assign Static Local IP to Your Server Rig
Open PowerShell, type ipconfig, and note your IPv4 Address (e.g. 192.168.1.150). Configure a static DHCP reservation in your router to prevent this IP from shifting upon reboot.
2Configure Router Port Forwarding (ASUS, TP-Link, Netgear, FRITZ!Box)
Log into your router admin panel (e.g. 192.168.1.1 or 192.168.178.1 for FRITZ!Box). For specific router hardware guides, see our ASUS guide or FRITZ!Box guide.
Rule 1: Port 2001 | Protocol: UDP | Target IP: [Your Static IP]
Rule 2: Port 17777 | Protocol: UDP | Target IP: [Your Static IP]
3Allow Inbound UDP Traffic in Windows Defender Firewall
Windows Firewall drops unsolicited incoming UDP packets by default. Run the one-click PowerShell script generated in our interactive calculator above to allow ports 2001 and 17777 UDP.
4Verify Connection and Share Direct Join Details
Test your public IP using our free NAT Checker diagnostic tool. Outside friends can join via the community browser or click Direct Connect and enter [YourPublicIP]:2001!
Trapped Behind DS-Lite or CGNAT? How to Host Arma Reforger
Did you follow every step above, create your router rules, and configure Windows Firewall, but outside players still cannot join or receive SERVER_UNREACHABLE?
The Hidden Roadblock: Carrier-Grade NAT (CGNAT) & European DS-Lite
In Germany, the UK, and across Europe (Vodafone, Deutsche Telekom, O2, Virgin Media) as well as American satellite/cellular providers (Starlink, T-Mobile Home Internet), ISPs no longer allocate public IPv4 addresses. Instead, they operate DS-Lite (Dual-Stack Lite) or CGNAT (RFC 6598).
Under DS-Lite / CGNAT, your router does not possess a public IPv4 address. Router port forwarding does nothing because the carrier gateway blocks all unsolicited incoming IPv4 packets before they ever reach your home.
Verify whether you are stuck in CGNAT in 10 seconds with our free online NAT Type & CGNAT test.
How to Host an Arma Reforger Scenario Without Port Forwarding
Gamers asking "how to host an arma reforger scenario without port forwarding" often find themselves stuck choosing between expensive monthly dedicated server rentals or giving up on multiplayer.
The ideal solution is using a VPN with Inbound Port Forwarding. By initiating an outbound tunnel to a VPN server that assigns you an open listening port, outside players can connect straight into your server with zero ISP port restrictions!
The Solution: A Low-Latency Port-Forwarding Gaming VPN
A gaming VPN with native port forwarding creates an encrypted WireGuard tunnel straight to a cloud endpoint. The VPN assigns you an open public port, eliminates DS-Lite and CGNAT hurdles, bypasses strict router firewalls, and conceals your real home residential IP from DDoS attacks!
This page contains affiliate links. If you sign up through them, NAT Checker may earn a commission at no extra cost to you.
Proton VPN
- 1-Click Inbound Port Forwarding toggle in desktop app (zero router hassle)
- High-speed WireGuard protocol with up to 10 Gbps server bandwidth
- Bypasses German DS-Lite, Starlink, and ISP CGNAT instantly
- Audited strict no-logs policy backed by Swiss privacy jurisdiction
- Built-in DDoS protection prevents malicious rivals from knocking your server offline
PureVPN
- Dedicated Port Forwarding add-on allows custom multi-port ranges
- Optional Dedicated Static IP ensures your community browser address stays fixed
- Compatible with Windows, Linux dedicated servers, and router-level tunnels
- Affordable multi-year pricing with a 31-day money-back guarantee
- Extensive global server presence across 65+ countries for optimal host ping
How to Host Arma Reforger with Proton VPN in 3 Minutes:
- Subscribe to Proton VPN and install the app on your host PC.
- In the app settings, navigate to Connection → Advanced and toggle Port Forwarding to ON.
- Connect to a nearby P2P-supported server. Proton VPN displays an active forwarded port number (e.g.
42890). - In your
server.json, set"bindPort": 42890and launch the server. - Give your squad your Proton VPN exit IP and the assigned port. Players will join instantly through CGNAT without touching your router!
Frequently Asked Questions: Arma Reforger Port Forwarding
What ports to forward for Arma Reforger?
Arma Reforger hosting requires forwarding port 2001 UDP for game network traffic and port 17777 UDP for the Steam server query list. Both must use the UDP protocol.
Is it safe to open port 25565 for Arma Reforger?
Port 25565 is strictly for Minecraft Java Edition. Arma Reforger servers do not listen on port 25565; opening it will not enable Arma Reforger connections.
Why isn't port 25565 open for Arma Reforger?
Port checkers report 25565 closed because Arma Reforger binds to ports 2001 and 17777 UDP, not 25565.
Should I enable port forwarding for gaming?
Port forwarding is required if you host a dedicated server, co-op scenario, or peer-to-peer game so incoming client packets reach your device. It is not necessary for standard client play.
Why does my Arma Reforger server appear on the list but remain unreachable?
The server query port (17777 UDP) responds to browser discovery, but the gameplay port (2001 UDP) is blocked by router NAT or Windows Firewall, or server.json binds to a local IP instead of 0.0.0.0.
How to host an Arma Reforger scenario without port forwarding?
You can rent a managed third-party game server or route your local PC server through a port-forwarding gaming VPN like Proton VPN or PureVPN to bypass router port restrictions completely.