Steam Datagram Relay

Valve's Steam Datagram Relay (SDR) is a virtual and private network that routes multiplayer content through Valve Corporation's server infrastructure. This network supports both peer-to-peer (P2P) and dedicated servers and is integrated into a variety of games.

The service (as well as the Connection Manager) is started when a game is first initialized and establishes a connection to the Internet, regardless of whether users want to use the multiplayer component or not.

The network can be used for P2P as well as dedicated servers and is active in numerous titles. The service runs during the first initialization and connects to the Internet. Whether users want to use a multiplayer component or not.

steam-datagram-relay.txt (7.58 KB)
Date: 2025-04-11
CRC32 Hash: a9b09037
SHA-256 Hash: 07d6eb645e4203b0d5a1f513ef76014b826c15ac0225b5e4f5486b788bf6dddc

One of the main advantages of SDR is the provision of faster ping times and independence from third-party server structures, such as Microsoft Corporation's Azure or Exit Games GmbH, which offers cross-platform real-time and multiplayer services under the name Photon.

Outgoing firewall traffic of the game Sol Cresta

As it turns out, the Ipv4 belongs to the address pool of SDR servers

Steam Datagram Relay (SDR)

Multiplayer features and traffic sent via Valve Corporations' backbones

The callback is always the same, "https://api.steampowered.com/ISteamApps/GetSDRConfig/v1?appid=xxxx", where xxxx is the SteamID of a given product, as in this example for The Planet Crafter

However, a potential disadvantage of SDR is that traffic can bypass hosts unfiltered, resulting in around three dozen IPv4 addresses being contacted in a single gaming session, even if the game does not offer any obvious multiplayer features.

This becomes particularly interesting when SDR is used for telemetry. To do this, developers must implement an interface between their game and the Steamworks API to send data to SDR. The data sent can contain various types of performance data, such as latency, packet loss, and bandwidth usage.

The transmitted data is then received by SDR and transmitted to a central storage location where it can be analyzed and evaluated. Developers can then use this data to improve the performance of their game and fix bugs.

Developers should ensure that all data sent is anonymized and encrypted and that users have the option to refuse to transmit telemetry data at any time.

A firewall of your choice is suitable for blocking.

Further information can be found via the Steamworks-Documentation  .