Port Forwarding Basics

Port forwarding is what lets players on the public internet reach a game server running behind your home router, ISP modem, or firewall.

The idea

Your swarm host machine usually has a private LAN address like 192.168.x.x, but players connect to your public IP.

When a player tries to reach <PUBLIC_IP>:<HOST_PORT>, your network equipment has to know where to send that traffic internally. A port-forward rule does that mapping:

  • Public side: <PUBLIC_IP>:<HOST_PORT>
  • Internal side: <SWARM_HOST_PRIVATE_IP>:<HOST_PORT>
  • Protocol: TCP or UDP, depending on the game

If the rule is missing or uses the wrong protocol, the deployment may be running but still be unreachable from the internet.

What Swarm checks

Swarm can show a Public Access status for deployments and the swarm host file gateway.

  • A green check means the configured public endpoint responded to an external probe.
  • A red X means the public endpoint could not be reached from the outside.
  • A yellow status means Swarm is still checking or the protocol needs a more specific probe.

This check uses the deployment's host ports and the swarm host's public address. It does not replace your router, firewall, or ISP configuration.

What you usually need to configure

  • Allow the game port on the host firewall.
  • Forward the same host port on your router or edge firewall to the swarm host machine.
  • Use the correct protocol for the game.
  • Make sure your ISP connection actually has a public IP and is not behind CGNAT.

We can't give one exact router guide

Every router UI is different, so Swarm does not try to document click-by-click instructions for every model.

Instead:

  1. Find your router or firewall model.
  2. Search for its port-forwarding guide from the vendor or community docs.
  3. Create a rule for the exact host port and protocol shown in Swarm.

Useful search examples:

  • ASUS RT-AX58U port forwarding UDP
  • UniFi port forwarding game server
  • TP-Link Archer port forwarding TCP UDP

Common blockers

  • Forwarding the wrong protocol
  • Forwarding to the wrong internal IP
  • Double NAT between modem and router
  • ISP CGNAT
  • Host firewall still blocking the port
  • Trying to use the swarm host's private IP from outside your network

If the File Gateway is failing

The swarm host file gateway also needs to be reachable from the public internet when you use direct browser-to-swarm host file transfers.

Check:

  • swarm host DNS points at the right public IP
  • the gateway port is allowed through the firewall
  • the hostname and TLS setup match your gateway configuration