Microsoft Windows Server · Rate Limits

Microsoft Windows Server Rate Limits

Windows Server platform APIs (PowerShell remoting, WinRM, WMI, IIS, ADWS) are typically consumed within the customer's own fabric over Kerberos / NTLM and are not subject to a Microsoft-imposed per-second rate limit. Throughput is bound by the customer's hardware, IIS request queue, WinRM MaxConcurrentOperations, and Active Directory throttling. There is no public throttling SLA for the OS itself.

4 Limits
Rate LimitingServerOperating SystemWindowsMicrosoft

Limits

WinRM concurrent operations (default) account
concurrent_requests
1500
Default MaxConcurrentOperationsPerUser per WinRM listener; tunable via Set-WSManInstance.
WinRM connections per user (default) account
concurrent_requests
25
Default MaxConcurrentUsers; configurable.
IIS HTTP request queue account
varies
Set per application pool via queueLength (default 1000); responses can be 503 when full
Active Directory LDAP MaxPageSize account
varies
1,000 entries per page (default); MaxPageSize / MaxQueryDuration tunable on the DC

Policies

Tune WinRM service quotas
WSMan provider settings (MaxConcurrentOperationsPerUser, MaxConnections, MaxConcurrentUsers) cap parallel remoting; tune per workload.
AD policy throttling
Active Directory enforces LdapAdminLimits (MaxPageSize, MaxQueryDuration, MaxConnIdleTime). Honor these in client query patterns.
503 from IIS
IIS returns 503 when application pool queues are full; clients should backoff and retry.

Sources