Table of Contents

Dedicated Server Compatibility

SteamNetworkLib supports two Schedule 1 networking modes through the same consumer API:

  • LobbyP2P: the vanilla game path, using Steam lobbies plus Steam P2P packets.
  • DedicatedRelay: a dedicated-server path, using DedicatedServerMod custom messaging. The server may route that messaging over FishNet RPC or Steam Networking Sockets.

Consumer mods should keep using SteamNetworkClient, ProcessIncomingMessages(), lobby/member data methods, and typed P2P messages. SteamNetworkLib detects the available backend at initialization and the active session mode at runtime.

Runtime Behavior

When the player is in a vanilla Steam lobby, SteamNetworkLib keeps using the existing Steam lobby and Steam P2P APIs.

When DedicatedServerMod is available, SteamNetworkLib can initialize its relay backend without client Steamworks. It reflects the DedicatedServerMod CustomMessaging API and registers a compatibility session once the messaging endpoint is ready. DedicatedServerMod then sends a virtual lobby snapshot containing:

  • local player SteamID
  • server SteamID when available
  • current member list
  • lobby data
  • per-member data

SteamNetworkLib exposes that snapshot through the normal high-level API:

client.IsInLobby;
client.IsHost;
client.LocalPlayerId;
client.CurrentLobby;
client.GetLobbyMembers();
client.SetMyData("MyMod_Version", "1.0.0");
await client.BroadcastMessageAsync(new TextMessage { Content = "Hello" });

P2P Semantics

In LobbyP2P, messages are sent through SteamNetworking.SendP2PPacket.

In DedicatedRelay, the same serialized SteamNetworkLib packet is sent to DedicatedServerMod, which forwards it to the target client or broadcasts it to session members. Logical P2P channel values are preserved so packet and message events report the same channel selected by the sender.

Reliability is still selected with the normal SNL APIs, but the dedicated path depends on the active DedicatedServerMod messaging backend for physical delivery. Operators can choose FishNetRpc or SteamNetworkingSockets in DedicatedServerMod configuration.

Consumer Guidance

Most mods do not need dedicated-server-specific code. Keep these practices:

  • Call client.Initialize() after Steam or DedicatedServerMod has loaded. Dedicated servers do not require client Steamworks.
  • Call client.ProcessIncomingMessages() every update tick.
  • Use client.IsInLobby instead of checking vanilla lobby internals.
  • Use client.IsHost for host-authoritative behavior. In dedicated sessions, the virtual owner is selected by the server compatibility layer.
  • Use GetLobbyMembers() and LocalPlayerId instead of caching vanilla Steam lobby state directly.

Do not replace Steam P2P code with dedicated-only logic. The library chooses the active route so the same mod can work in vanilla lobbies and dedicated-server sessions.

Edit this page