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Troubleshooting: Steam Connectivity - How to Force TCP with the -tcp Parameter

The -tcp parameter in Steam compels the client to utilize TCP (Transmission Control Protocol) instead of UDP (User Datagram Protocol) for network communication. This is particularly useful in scenarios where UDP is blocked or encounter issues.


🛠️ When to Use -tcp in Steam


You may benefit from using the -tcp launch option in the following scenarios:


  • Firewall or Network Restrictions

If UDP traffic is blocked by a firewall or network admin, switching to TCP can help Steam connect successfully.

  • Network Congestion

In congested networks, TCP’s reliability may result in a more stable (though possibly slower) connection.

  • Troubleshooting Connectivity Issues

Using -tcp can help identify if UDP is the root of your Steam connection problems.



🔧 How to Configure Steam with the -tcp Parameter


You can apply the -tcp setting either through a shortcut or via Steam's internal settings.



Method 1: Add -tcp to a Steam Shortcut


This method applies only when launching Steam via the modified shortcut.


  1. Locate Your Steam Shortcut

Find the Steam shortcut on your desktop or Start Menu.

  1. Edit Shortcut Properties

Right-click the shortcut and select Properties.

  1. Modify the Target Field

In the Shortcut tab, find the Target field.

  1. Append -tcp

After the file path, add a space followed by -tcp.


Example:

"C:\Program Files (x86)\Steam\Steam.exe" -tcp

  1. Apply Changes

Click Apply, then OK.

  1. Launch Steam

Open Steam using the modified shortcut.



Method 2: Set -tcp via Steam Launch Options


This method affects all games launched through Steam.


  1. Open Steam

Launch your Steam client.

  1. Go to Settings

Click Steam in the top-left corner > Settings.

  1. Enable Developer Tools (Optional)

Under the Interface tab, enable:

“Display Steam URL address bar when available”

  1. Open the Developer Console

Click View > Console.

  1. Launch the Launch Options Window

In the console, type:

open steam://open/settings/launchoptions

  1. Enter -tcp

In the launch options box, add -tcp.

  1. Restart Steam

Fully close and reopen Steam for the change to take effect.



⚠️ Important Notes


  • May Affect Performance

TCP may introduce higher latency, which can negatively impact gameplay, especially in fast-paced online titles.

  • Use for Troubleshooting Only

If used for diagnosing issues, remove the -tcp flag afterward for optimal performance.

  • Review Network Setup

Persistent UDP issues may indicate a misconfigured network or restrictive firewall settings.

  • Game-Specific Settings

Some games have internal network settings that may override Steam’s connection preferences.



🔗 Additional Resource


For details on required Steam ports, visit:

Steam Network Ports FAQ

Updated on: 17/12/2025

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