IIS and Related Upload Limit Settings (en-AU)

This article will attempt to pull the various settings that might restrict uploads into an IIS-based web server into an easy-to-check list.

IIS (6.0 and above) uses HTTP.SYS as the kernel-mode HTTP listener, and frequently runs an application-layer framework like ASP or ASP.Net, as well as ISAPI filters, modules and handlers, all of which can implement different limits, or change request/response behaviours.

If you encounter a limit in a particular component, please add it to this list.

IIS 7.x

HTTP.SYS

• MaxRequestBytes http://support.microsoft.com/kb/820129

IIS

• Request Filtering RequestLimits MaxAllowedContentLength http://www.iis.net/ConfigReference/system.webServer/security/requestFiltering/requestLimits
• Also MaxHeaderLimits sizelimit (just for headers)
• MaxRequestEntityAllowed (ServerRuntime) (default: unlimited) - http://msdn.microsoft.com/en-us/library/aa347568(v=VS.90).aspx 

ASP

• MaxRequestEntityAllowed http://www.iis.net/ConfigReference/system.webServer/asp/limits

ASP.Net

• httpRuntime MaxRequestLength
  • Discussion http://support.microsoft.com/default.aspx?scid=kb;EN-US;295626 
  • Reference http://msdn.microsoft.com/en-us/library/e1f13641.aspx

Probably unrelated unless dealing with thousands of concurrent requests and/or uploads:

• appConcurrentRequestLimit - http://msdn.microsoft.com/en-us/library/aa347568(v=VS.90).aspx

IIS 6.0

HTTP.SYS - as above
ASP

• AspMaxRequestEntityAllowed (200,000 default - results in 403 when exceeded)

ASP.Net as above