Throttle a single executable outbound with a Windows policy, without installing a traffic shaper on the network.
Create a **policy-based QoS** rule with `New-NetQosPolicy` that matches the executable path and sets a throttle rate, then confirm it with `Get-NetQosPolicy`. The rule only shapes traffic the machine sends.
Launchers spawn helper processes. The updater that saturates the line is often a second exe next to the first, so read the paths instead of guessing the name.
Get-Process | Where-Object Path | Select-Object Name,Path -Unique | Sort-Object NameThe rate is in bits per second, so ten megabits is ten million and not ten megabytes. Writing the number out avoids the unit trap that makes a rule either useless or brutal.
New-NetQosPolicy -Name SteamLimit -AppPathNameMatchCondition C:\Program Files (x86)\Steam\steam.exe -ThrottleRateActionBitsPerSecond 10000000One policy matches one path. A launcher with a separate updater needs its own rule, otherwise the limit applies to the quiet process and misses the busy one.
New-NetQosPolicy -Name SteamHelperLimit -AppPathNameMatchCondition C:\Program Files (x86)\Steam\bin\cef\cef.win7x64\steamwebhelper.exe -ThrottleRateActionBitsPerSecond 5000000The cmdlet lists every rule with its conditions. A rule with a wrong path applies to nothing and reports no error at creation time.
Get-NetQosPolicy | Format-List Name,AppPathName,ThrottleRateRun the same download before and after the rule is in place. Task Manager per-process network columns show the rate the application actually achieves.
Get-NetTCPConnection -State Established | Group-Object OwningProcess | Sort-Object Count -Descending | Select-Object -First 5A forgotten throttle makes a client look broken months later, and nobody remembers creating it. Clean up after the experiment.
Remove-NetQosPolicy -Name SteamLimit -Confirm:$falseThe wrong executable, or the traffic comes from another process. Check the connection list for the owning process ID.
QoS shapes outgoing traffic only. Incoming downloads are limited by the sender; do that on the router.
The NetQos module needs an elevated session and a Pro or Enterprise build.
The rate was given in bytes rather than bits. Multiply by eight for the intended value.
No, policies are per machine and apply to every session.
Yes, the same cmdlet offers a DSCP value, but routers must honour it for any effect.
Remove-NetQosPolicy -Name followed by the rule name deletes it immediately; no restart is required.
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