FTP Connections <connections>

Overview

The <connections> element specifies the connection-related settings for FTP sites. More specifically, the settings in the <connections> element control the behavior for the FTP service with regard to how to manage clients that are connecting to an FTP site.

For example, the unauthenticatedTimeout, controlChannelTimeout, and dataChannelTimeout attributes specify the time-outs for an FTP site. The settings specify, respectively, when the FTP service will disconnect an FTP client that has not successfully logged in or is idle, or when to disconnect an idle data connection. Specifying values for the attributes in the <connections> element can directly affect the overall performance of your server by helping to police the number of active client sessions for your FTP sites.

Compatibility

Version Notes
IIS 7.5 The <connections> element of the <ftpServer> element ships as a feature of IIS 7.5.
IIS 7.0 The <connections> element of the <ftpServer> element was introduced in FTP 7.0, which was a separate download for IIS 7.0.
IIS 6.0 N/A

Note: The FTP 7.0 and FTP 7.5 services shipped out-of-band for IIS 7.0, which required downloading and installing the modules from the following URL:

http://www.iis.net/expand/FTP

With Windows 7 and Windows Server 2008 R2, the FTP 7.5 service ships as a feature for IIS 7.5, so downloading the FTP service is no longer necessary.

Setup

To support FTP publishing for your Web server, you must install the FTP service. To do so, use the following steps.

IIS 7.5 for Windows Server 2008 R2

  1. On the taskbar, click Start, point to Administrative Tools, and then click Server Manager.
  2. In the Server Manager hierarchy pane, expand Roles, and then click Web Server (IIS).
  3. In the Web Server (IIS) pane, scroll to the Role Services section, and then click Add Role Services.
  4. On the Select Role Services page of the Add Role Services Wizard, expand FTP Server.
  5. Select FTP Service.

    Note: To support ASP.Membership authentication or IIS Manager authentication for the FTP service, you will also need to select FTP Extensibility.
  6. Click Next.
  7. On the Confirm Installation Selections page, click Install.
  8. On the Results page, click Close.

IIS 7.5 for Windows 7

  1. On the taskbar, click Start, and then click Control Panel.
  2. In Control Panel, click Programs and Features, and then click Turn Windows Features on or off.
  3. Expand Internet Information Services, and then FTP Server.
  4. Select FTP Service.

    Note: To support ASP.Membership authentication or IIS Manager authentication for the FTP service, you will also need to select FTP Extensibility.
  5. Click OK.

IIS 7.0 for Windows Server 2008 and Windows Vista

  1. Download the installation package from the following URL:
  2. Follow the instructions in the following walkthrough to install the FTP service:

How To

How to configure the control and data channel time-outs for an FTP 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 Manage FTP Site section of the Actions pane.
  4. In the Advanced Settings dialog box, expand Connections, specify your time-outs in the Control Channel Timeout and Data Channel Timeout fields, and then click OK.

Configuration

The <connections> element is configured at the site level.

Attributes

Attribute Description
controlChannelTimeout Optional int attribute.

Specifies the timeout, in seconds, when a connection will be timed out because of inactivity on the control channel. Note: The FTP service will disconnect the session when this timeout is reached.

The default value is 120.
dataChannelTimeout Optional int attribute.

Specifies the timeout, in seconds, when a connection will be timed out because of inactivity on the data channel. Note: The FTP service will only disconnect the data channel when this timeout is reached.

The default value is 30.
disableSocketPooling

Optional Boolean attribute.

true if socket pooling is disabled; otherwise, false.

The disableSocketPooling attribute specifies whether socket pooling is used for sites that are distinguished by IP address rather than port number or host name. If disableSocketPooling is set to false, then socket pooling is enabled and sockets are shared between sites that use the same socket number but different IP addresses. In this situation, the FTP service becomes the exclusive owner of the port on each address that is bound to the server. For example, if socket pooling is enabled on a server that has two IP addresses, 10.0.0.1 and 10.0.0.2, and an FTP site is bound to address 10.0.0.1 on port 21, the FTP service will also own port 21 on the 10.0.0.2 address. If disableSocketPooling is set to true, then there is no socket sharing for sites based on IP address.

The default value is false.

maxBandwidth Unused uint attribute.

Note: This attribute is not implemented for FTP 7.
maxConnections Optional unit attribute.

Specifies the maximum number of simultaneous connections for an FTP site.

Note: Use the maxClientsMessage attribute of the <messages> element to specify a message that the FTP service will return to clients when the maximum number of simultaneous connections has been exceeded.

The default value is 4294967295 (unlimited.)
minBytesPerSecond Optional int attribute.

Specifies the minimum bandwidth requirements for data transfers. Note: The FTP service will disconnect the data channel when the minimum bandwidth is not met.

The default value is 240.
resetOnMaxConnections Optional Boolean attribute.

true if the FTP service should quickly disconnect an FTP session instead of sending a maximum connections response; otherwise false.

Note: The resetOnMaxConnections attribute optimizes the overhead when processing connections that are not allowed to connect because maxConnection limit was reached.

The default value is false.
serverListenBacklog Optional int attribute.

Specifies the number of outstanding sockets that can be queued.

The default value is 60.
unauthenticatedTimeout Optional int attribute.

Specifies the idle time-out, in seconds, between when a new connection is made and authentication succeeds. If the client does not successfully authenticate within the specified time period, the FTP service will disconnect the session.

The default value is 30.

Child Elements

None.

Configuration Sample

The following sample displays a <connections> element for an FTP site that defines a control channel time-out of 120 seconds and a data channel time-out of 30 seconds.

<site name="ftp.example.com" id="5">
  <application path="/">
    <virtualDirectory path="/" physicalPath="c:\inetpub\www.example.com" />
  </application>
  <bindings>
    <binding protocol="ftp" bindingInformation="*:21:" />
  </bindings>
  <ftpServer>
   <connections controlChannelTimeout="120" dataChannelTimeout="30" />
    <security>
      <authentication>
        <basicAuthentication enabled="true" />
        <anonymousAuthentication enabled="false" />
      </authentication>
    </security>
  </ftpServer>
</site>

Sample Code

The following examples configure an FTP site with a control channel time-out of 120 seconds and a data channel time-out of 30 seconds.

AppCmd.exe

appcmd.exe set config -section:system.applicationHost/sites /[name='ftp.example.com'].ftpServer.connections.controlChannelTimeout:"120" /commit:apphost

appcmd.exe set config -section:system.applicationHost/sites /[name='ftp.example.com'].ftpServer.connections.dataChannelTimeout:"30" /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", @"ftp.example.com");
         if (siteElement == null) throw new InvalidOperationException("Element not found!");
         ConfigurationElement ftpServerElement = siteElement.GetChildElement("ftpServer");

         ConfigurationElement connectionsElement = ftpServerElement.GetChildElement("connections");
         connectionsElement["controlChannelTimeout"] = 120;
         connectionsElement["dataChannelTimeout"] = 30;

         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", "ftp.example.com")
      If (siteElement Is Nothing) Then
         Throw New InvalidOperationException("Element not found!")
      End If
      Dim ftpServerElement As ConfigurationElement = siteElement.GetChildElement("ftpServer")

      Dim connectionsElement As ConfigurationElement = ftpServerElement.GetChildElement("connections")
      connectionsElement("controlChannelTimeout") = 120
      connectionsElement("dataChannelTimeout") = 30

      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", "ftp.example.com"]);
if (siteElementPos == -1) throw "Element not found!";
var siteElement = sitesCollection.Item(siteElementPos);
var ftpServerElement = siteElement.ChildElements.Item("ftpServer");

var connectionsElement = ftpServerElement.ChildElements.Item("connections");
connectionsElement.Properties.Item("controlChannelTimeout").Value = 120;
connectionsElement.Properties.Item("dataChannelTimeout").Value = 30;

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 = 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", "ftp.example.com"))
If siteElementPos = -1 Then
   WScript.Echo "Element not found!"
   WScript.Quit
End If
Set siteElement = sitesCollection.Item(siteElementPos)
Set ftpServerElement = siteElement.ChildElements.Item("ftpServer")

Set connectionsElement = ftpServerElement.ChildElements.Item("connections")
connectionsElement.Properties.Item("controlChannelTimeout").Value = 120
connectionsElement.Properties.Item("dataChannelTimeout").Value = 30

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