FTP Firewall Support <firewallSupport>

Overview

The <system.ftpServer/firewallSupport> element is used to configure the port range that the FTP service will use for data channel activity when when you use the FTP PASV command to negotiate passive connections, which contains IP address and port of the server.

When passive connections are negotiated using the FTP PASV command, the FTP server sends a response which contains IP address and port of the server. By specifying the lowDataChannelPort and highDataChannelPort attributes, you can direct FTP clients to communicate with your firewall, which should route the client traffic to your FTP server.

The valid range for TCP/IP ports is 1025 through 65535. (Ports from 1 through 1024 are reserved for use by system services.) You can enter a special port range of "0-0" to configure the FTP server to use the Windows TCP/IP ephemeral port range. In early versions of Windows, the TCP/IP ephemeral port range was set to use ports 1025 through 5000. Starting with Windows Vista and Windows Server 2008, the TCP/IP ephemeral port range has been changed to 49152 through 65535. For more information about the ephemeral port range, see the following article in the Microsoft Knowledge Base:

929851: The default dynamic port range for TCP/IP has changed in Windows Vista and in Windows Server 2008

Note: You can use the <ftpServer/firewallSupport> to configure the per-site external IP address for your firewall; this allows you to route the firewall traffic for each site through a different firewall.

Compatibility

Version Notes
IIS 7.5 The <firewallSupport> element of the <system.ftpServer> element ships as a feature of IIS 7.5.
IIS 7.0 The <firewallSupport> element of the <system.ftpServer> element was introduced in FTP 7.0, which was a separate download for IIS 7.0.
IIS 6.0 The <firewallSupport> element replaces the IIS 6.0 MSFTPSVC/PassivePortRange metabase property.

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 global firewall settings for the FTP service

  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, click the server name.
  3. In the Home pane, double-click the FTP Firewall Support feature.
  4. In the Data Channel Port Range box, use one of the following options to enter a port range for passive data channel connections:
    • Use [low port]-[high port] for a port range, where each port must be between 1025 and 65535. For example, 5000-6000.
    • Use "0-0" to configure the FTP server to use the Windows TCP/IP ephemeral port range.
  5. In the External IP Address of Firewall box, type the IPv4 address of the Internet-facing network adapter of your firewall.
  6. In the Actions pane, click Apply.

For additional information about how to configure the firewall settings for the FTP service, see the following topic on the Microsoft IIS.net Web site:

Configuring FTP Firewall Settings
http://learn.iis.net/page.aspx/309/configuring-ftp-firewall-settings/

Configuration

The <firewallSupport> element is configured at the global level in ApplicationHost.config.

Attributes

Attribute Description
lowDataChannelPort Optional int attribute.

Specifies the lowest port for data channel activity for passive data connections.

The default value is 0.
highDataChannelPort Optional int attribute.

Specifies the lowest port for data channel activity for passive data connections.

The default value is 0.

Child Elements

None.

Configuration Sample

The following sample illustrates several configuration settings in the global <system.ftpServer> element for a server. More specifically, the settings in this example demonstrate how to:

  • Enable FTP credential caching and specify a time-out of 10 minutes (600 seconds.)
  • Configure the low port as 5000 and the high port as 6000 for data channel communications.
  • Enable logging and specify that log files will be kept per-site, and that log files will be rotated daily by UTC time.
  • Specify a custom FTP provider and specify a custom parameter for that provider.
  • Specify global IP restrictions that allow FTP access from local host and deny access to the 169.254.0.0 to 169.254.255.255 block of IP addresses.
  • Configure request filtering with the following options:
    • Block FTP access to the _vti_bin virtual directory, which is used with the FrontPage Server Extensions.
    • Block several file types that are associated with executables.
    • Specify 100MB as the maximum file size.
  • Add a global authorization rule that allows access for the administrators group.
  • Specify that domain name syntax can be used for FTP virtual host names.
<system.ftpServer>
   <caching>
      <credentialsCache enabled="true" flushInterval="600" />
   </caching>
   <firewallSupport lowDataChannelPort="5000" highDataChannelPort="6000" />
   <log centralLogFileMode="Site">
      <centralLogFile period="Daily" localTimeRollover="false" enabled="true" />
   </log>
   <providerDefinitions>
      <add name="FtpXmlAuthentication"
         type="FtpXmlAuthentication, FtpXmlAuthentication, version=1.0.0.0, Culture=neutral, PublicKeyToken=426f62526f636b73" />
      <activation>
         <providerData name="FtpXmlAuthentication">
            <add key="xmlFileName" value="C:\Inetpub\XmlSample\Users.xml" />
         </providerData>
      </activation>
   </providerDefinitions>
   <security>
      <ipSecurity enableReverseDns="false" allowUnlisted="true">
         <add ipAddress="169.254.0.0" subnetMask="255.255.0.0" allowed="false" />
         <add ipAddress="127.0.0.1" allowed="true" />
      </ipSecurity>
      <requestFiltering>
         <hiddenSegments>
            <add segment="_vti_bin" />
         </hiddenSegments>
         <fileExtensions allowUnlisted="true">
            <add fileExtension="exe" allowed="false" />
            <add fileExtension="cmd" allowed="false" />
            <add fileExtension="com" allowed="false" />
            <add fileExtension="bat" allowed="false" />
         </fileExtensions>
         <requestLimits maxAllowedContentLength="104857600" />
      </requestFiltering>
      <authorization>
         <add accessType="Allow" roles="administrators" permissions="Read, Write" />
      </authorization>
   </security>
   <serverRuntime>
      <hostNameSupport useDomainNameAsHostName="true" />
   </serverRuntime>
</system.ftpServer>

Sample Code

The following examples configure the FTP service to use the port range of 5000 to 6000 for data channel activity when passive connections are used.

AppCmd.exe

appcmd.exe set config -section:system.ftpServer/firewallSupport /lowDataChannelPort:"5000" /commit:apphost

appcmd.exe set config -section:system.ftpServer/firewallSupport /highDataChannelPort:"6000" /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 logSection = config.GetSection("system.ftpServer/log");
         logSection["centralLogFileMode"] = @"Central";

         ConfigurationElement centralLogFileElement = logSection.GetChildElement("centralLogFile");
         centralLogFileElement["enabled"] = true;

         serverManager.CommitChanges();
      }
   }
}

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 firewallSupportSection As ConfigurationSection = config.GetSection("system.ftpServer/firewallSupport")
      firewallSupportSection("lowDataChannelPort") = 5000
      firewallSupportSection("highDataChannelPort") = 6000

      serverManager.CommitChanges()
   End Sub
End Module

JavaScript

var adminManager = new ActiveXObject('Microsoft.ApplicationHost.WritableAdminManager');
adminManager.CommitPath = "MACHINE/WEBROOT/APPHOST";

var firewallSupportSection = adminManager.GetAdminSection("system.ftpServer/firewallSupport", "MACHINE/WEBROOT/APPHOST");
firewallSupportSection.Properties.Item("lowDataChannelPort").Value = 5000;
firewallSupportSection.Properties.Item("highDataChannelPort").Value = 6000;

adminManager.CommitChanges();

VBScript

Set adminManager = createObject("Microsoft.ApplicationHost.WritableAdminManager")
adminManager.CommitPath = "MACHINE/WEBROOT/APPHOST"

Set firewallSupportSection = adminManager.GetAdminSection("system.ftpServer/firewallSupport", "MACHINE/WEBROOT/APPHOST")
firewallSupportSection.Properties.Item("lowDataChannelPort").Value = 5000
firewallSupportSection.Properties.Item("highDataChannelPort").Value = 6000

adminManager.CommitChanges()
Deprecated Elements