Link multiple Minecraft servers (BungeeCord/Velocity)

A proxy (Velocity, Waterfall, or BungeeCord) links several Minecraft servers under a single IP address. Players connect to the proxy and switch between servers (lobby, survival, creative) without disconnecting. Velocity is the recommended modern option.

Cause / The problem

Without a proxy, each server has its own IP and players must disconnect/reconnect to move between them, losing inventory and state. A proxy unifies everything but requires secure authentication between the proxy and the backend servers to prevent spoofing.

Solution

1. Prepare your servers: 1 proxy + at least 2 backend servers (e.g. lobby, survival). All backends must run Paper/Spigot; the proxy is Velocity, Waterfall, or BungeeCord.
2. On each backend, switch to online-mode=false in server.properties: it’s the proxy that handles Mojang authentication.

   online-mode=false

3. For Velocity, enable modern forwarding in each backend’s paper-global.yml:

   proxies:
     velocity:
       enabled: true
       secret: 'a-long-secret-string'
       online-mode: true

4. Configure the proxy in velocity.toml:

   player-info-forwarding-mode = "modern"
   forwarding-secret-file = "forwarding.secret"

   Velocity auto-generates a forwarding.secret — copy its contents into each backend’s paper-global.yml (both must match).
5. Declare your servers in velocity.toml:

   [servers]
   lobby = "127.0.0.1:25566"
   survival = "127.0.0.1:25567"
   creative = "127.0.0.1:25568"

6. Firewall: expose only the proxy port (25565). Backends must only be reachable from the proxy — otherwise an attacker can bypass authentication.
7. For BungeeCord, use ip_forward: true in config.yml instead, and install BungeeGuard to secure it (BungeeCord’s legacy forwarding is weak).
8. Test: connect to the proxy and type /server survival (with the SlashServer plugin, or via Velocity commands).

Modern forwarding with a secret is what stops anyone from spinning up a fake proxy and sending forged player data to the backends. Never reuse the same secret across different servers.