Limits for a Web Site <limits>

Overview

The <limits> element of the <site> element configures settings that limit the amount of bandwidth, the number of connections, or the connection time-out for client requests to a site.

Note: If the <limits> element is configured in both the <siteDefaults> section and in the <site> section for a specific site, the configuration in the <site> section is used for that site.

Compatibility

Version Notes
IIS 7.5 The <limits> element was not modified in IIS 7.5.
IIS 7.0 The <limits> element of the <site> element was introduced in IIS 7.0.
IIS 6.0 The <limits> element replaces the following IIS 6.0 metabase settings:
  • ConnectionTimeout
  • MaxBandwidth
  • MaxConnections

Setup

The <limits> element of the <site> element is included in the default installation of IIS 7.

How To

How to configure the connection limit options for a site

  1. Open Internet Information Services (IIS) Manager:
    • If you are using Windows Server 2008 or Windows Server 2008 R2:
      • On the taskbar, click Start, point to Administrative Tools, and then click Internet Information Services (IIS) Manager.
    • If you are using Windows Vista or Windows 7:
      • On the taskbar, click Start, and then click Control Panel.
      • Double-click Administrative Tools, and then double-click Internet Information Services (IIS) Manager.
  2. In the Connections pane, expand the server name, expand the Sites node, and then click the name of the site.
  3. In the site's Home pane, click Advanced Settings... in the Actions pane.

  4. In the Advanced Settings dialog box, expand Connection Limits, specify connection limit options, and then click OK.

Configuration

Attributes

Attribute Description
connectionTimeout Optional timeSpan attribute.

Specifies the time (in seconds) that IIS waits before it disconnects a connection that is considered inactive. Connections can be considered inactive for the following reasons:
  • The HTTP.sys Timer_ConnectionIdle timer expired. The connection expired and remains idle.
  • The HTTP.sys Timer_EntityBody timer expired. The connection expired before the request entity body arrived. When it is clear that a request has an entity body, the HTTP API turns on the Timer_EntityBody timer. Initially, the limit of this timer is set to the connectionTimeout value. Each time another data indication is received on this request, the HTTP API resets the timer to give the connection more minutes as specified in the connectionTimeout attribute.
  • The HTTP.sys Timer_AppPool timer expired. The connection expired because a request waited too long in an application pool queue for a server application to dequeue and process it. This time-out duration is connectionTimeout.

The default value is 00:02:00 (two minutes).

maxBandwidth Optional uint attribute.

Specifies the maximum network bandwidth, in bytes per second, that is used for a site. Use this setting to help prevent overloading the network with IIS activity.

The default value is 4294967295.
maxConnections Optional uint attribute.

Specifies the maximum number of connections for a site. Use this setting to limit the number of simultaneous client connections.

The default value is 4294967295.

Child Elements

None.

Configuration Sample

The following configuration sample shows a Web site where the maximum bandwidth is set to 65,536 bytes per second, the maximum number of connections is set to 1024 , and the connection time-out is set to 1 minute.

<sites>
   <site name="Default Web Site" id="1" serverAutoStart="true">
      <application path="/">
         <virtualDirectory path="/"
            physicalPath="%SystemDrive%\inetpub\wwwroot" />
      </application>
      <bindings>
         <binding protocol="http"
            bindingInformation="*:80:" />
      </bindings>
     <limits maxBandwidth="65536"
         maxConnections="1024"
         connectionTimeout="00:01:00" />
   </site>
</sites>

Sample Code

The following code samples configure the Default Web Site for a maximum bandwidth of 65,536 bytes per second, 1024 maximum connections, and a connection time-out of 1 minute.

AppCmd.exe

appcmd.exe set config -section:system.applicationHost/sites "/[name='Default Web Site'].limits.maxBandwidth:65536" /commit:apphost
appcmd.exe set config -section:system.applicationHost/sites "/[name='Default Web Site'].limits.maxConnections:1024" /commit:apphost
appcmd.exe set config -section:system.applicationHost/sites "/[name='Default Web Site'].limits.connectionTimeout:00:01:00" /commit:apphost

Note: You must be sure to set the commit parameter to apphost when you use AppCmd.exe to configure these settings. This commits the configuration settings to the appropriate location section in the ApplicationHost.config file.

C#

using System;
using System.Text;
using Microsoft.Web.Administration;

internal static class Sample
{
   private static void Main()
   {
      using (ServerManager serverManager = new ServerManager())
      {
         Configuration config = serverManager.GetApplicationHostConfiguration();
         ConfigurationSection sitesSection = config.GetSection("system.applicationHost/sites");
         ConfigurationElementCollection sitesCollection = sitesSection.GetCollection();

         ConfigurationElement siteElement = FindElement(sitesCollection, "site", "name", @"Default Web Site");
         if (siteElement == null) throw new InvalidOperationException("Element not found!");

         ConfigurationElement limitsElement = siteElement.GetChildElement("limits");
         limitsElement["maxBandwidth"] = 65536;
         limitsElement["maxConnections"] = 1024;
         limitsElement["connectionTimeout"] = TimeSpan.Parse("00:01:00");

         serverManager.CommitChanges();
      }
   }

   private static ConfigurationElement FindElement(ConfigurationElementCollection collection, string elementTagName, params string[] keyValues)
   {
      foreach (ConfigurationElement element in collection)
      {
         if (String.Equals(element.ElementTagName, elementTagName, StringComparison.OrdinalIgnoreCase))
         {
            bool matches = true;
            for (int i = 0; i < keyValues.Length; i += 2)
            {
               object o = element.GetAttributeValue(keyValues[i]);
               string value = null;
               if (o != null)
               {
                  value = o.ToString();
               }
               if (!String.Equals(value, keyValues[i + 1], StringComparison.OrdinalIgnoreCase))
               {
                  matches = false;
                  break;
               }
            }
            if (matches)
            {
               return element;
            }
         }
      }
      return null;
   }
}

VB.NET

Imports System
Imports System.Text
Imports Microsoft.Web.Administration

Module Sample
   Sub Main()
      Dim serverManager As ServerManager = New ServerManager
      Dim config As Configuration = serverManager.GetApplicationHostConfiguration
      Dim sitesSection As ConfigurationSection = config.GetSection("system.applicationHost/sites")
      Dim sitesCollection As ConfigurationElementCollection = sitesSection.GetCollection

      Dim siteElement As ConfigurationElement = FindElement(sitesCollection, "site", "name", "Default Web Site")
      If (siteElement Is Nothing) Then
         Throw New InvalidOperationException("Element not found!")
      End If

      Dim limitsElement As ConfigurationElement = siteElement.GetChildElement("limits")
      limitsElement("maxBandwidth") = 65536
      limitsElement("maxConnections") = 1024
      limitsElement("connectionTimeout") = TimeSpan.Parse("00:01:00")

       serverManager.CommitChanges()
   End Sub

   Private Function FindElement(ByVal collection As ConfigurationElementCollection, ByVal elementTagName As String, ByVal ParamArray keyValues() As String) As ConfigurationElement
      For Each element As ConfigurationElement In collection
         If String.Equals(element.ElementTagName, elementTagName, StringComparison.OrdinalIgnoreCase) Then
            Dim matches As Boolean = True
            Dim i As Integer
            For i = 0 To keyValues.Length - 1 Step 2
               Dim o As Object = element.GetAttributeValue(keyValues(i))
               Dim value As String = Nothing
               If (Not (o) Is Nothing) Then
                  value = o.ToString
               End If
               If Not String.Equals(value, keyValues((i + 1)), StringComparison.OrdinalIgnoreCase) Then
                  matches = False
                  Exit For
               End If
            Next
            If matches Then
               Return element
            End If
         End If
      Next
      Return Nothing
   End Function

End Module

JavaScript

var adminManager = new ActiveXObject('Microsoft.ApplicationHost.WritableAdminManager');
adminManager.CommitPath = "MACHINE/WEBROOT/APPHOST";
var sitesSection = adminManager.GetAdminSection("system.applicationHost/sites", "MACHINE/WEBROOT/APPHOST");

var sitesCollection = sitesSection.Collection;
var siteElementPos = FindElement(sitesCollection, "site", ["name", "Default Web Site"]);
if (siteElementPos == -1) throw "Element not found!";
var siteElement = sitesCollection.Item(siteElementPos);

var limitsElement = siteElement.ChildElements.Item("limits");
limitsElement.Properties.Item("maxBandwidth").Value = 65536;
limitsElement.Properties.Item("maxConnections").Value = 1024;
limitsElement.Properties.Item("connectionTimeout").Value = "00:01:00";

adminManager.CommitChanges();

function FindElement(collection, elementTagName, valuesToMatch) {
   for (var i = 0; i < collection.Count; i++) {
      var element = collection.Item(i);
      if (element.Name == elementTagName) {
         var matches = true;
         for (var iVal = 0; iVal < valuesToMatch.length; iVal += 2) {
            var property = element.GetPropertyByName(valuesToMatch[iVal]);
            var value = property.Value;
            if (value != null) {
               value = value.toString();
            }
            if (value != valuesToMatch[iVal + 1]) {
               matches = false;
               break;
            }
         }
         if (matches) {
            return i;
         }
      }
   }
   return -1;
}

VBScript

Set adminManager = WScript.CreateObject("Microsoft.ApplicationHost.WritableAdminManager")
adminManager.CommitPath = "MACHINE/WEBROOT/APPHOST"
Set sitesSection = adminManager.GetAdminSection("system.applicationHost/sites", "MACHINE/WEBROOT/APPHOST")

Set sitesCollection = sitesSection.Collection
siteElementPos = FindElement(sitesCollection, "site", Array("name", "Default Web Site"))
If siteElementPos = -1 Then
   WScript.Echo "Element not found!"
   WScript.Quit
End If
Set siteElement = sitesCollection.Item(siteElementPos)

Set limitsElement = siteElement.ChildElements.Item("limits")
limitsElement.Properties.Item("maxBandwidth").Value = 65536
limitsElement.Properties.Item("maxConnections").Value = 1024
limitsElement.Properties.Item("connectionTimeout").Value = "00:01:00"

adminManager.CommitChanges()

Function FindElement(collection, elementTagName, valuesToMatch)
   For i = 0 To CInt(collection.Count) - 1
      Set element = collection.Item(i)
      If element.Name = elementTagName Then
         matches = True
         For iVal = 0 To UBound(valuesToMatch) Step 2
            Set property = element.GetPropertyByName(valuesToMatch(iVal))
            value = property.Value
            If Not IsNull(value) Then
               value = CStr(value)
            End If
            If Not value = CStr(valuesToMatch(iVal + 1)) Then
               matches = False
               Exit For
            End If
         Next
         If matches Then
            Exit For
         End If
      End If
   Next
   If matches Then
      FindElement = i
   Else
      FindElement = -1
   End If
End Function
Deprecated Elements