Automatically Creating Checksum Files for FTP Uploads

I had a great question in the publishing forums on forums.iis.net, where someone was asking if FTP 7 supported the XCRC command. The short answer is that the XCRC command is not supported, but I came up with a way to create an FTP provider that supports something like it. Since it was a rather fun code sample to write, I thought that I'd turn it into a blog.

The sample FTP provider code in this blog post will automatically calculate an MD5 checksum from a file that is uploaded and store it in a file with a "*.MD5.TXT" file name extension. You can then compare the uploaded checksum with a local checksum on the client to verify the uploaded file's integrity.

There are a few points that I need to discuss before I present the code sample:

  • I chose to use MD5 because it is built-in to the .NET System.Security.Cryptography namespace and I often like to use MD5 for file checksums. I could just have easily implemented SHA1, SHA256, or any of the other built-in hashing algorithms. Unfortunately, CRC32 is not a built-in algorithm for .NET, but a quick search around the Internet yielded several CRC32 samples in C# from various developers, so if you specifically need the CRC32 algorithm you can find it pretty quickly and substitute it for MD5 in my example. (You can click here to search for examples.) You could go one step further and have your provider support multiple checksum algorithms, but that's going way outside the scope of this blog.
  • There are a couple of security considerations for this provider:
    • The provider needs to calculate the path of the uploaded file, and to do so requires calling into the IIS configuration APIs. As I mention in the code remarks:
      • The FTP service will host the compiled assembly in the "Microsoft FTP Service Extensibility Host" COM+ package (DLLHOST.EXE), which runs by default as NETWORK SERVICE.
      • Also by default, the NETWORK SERVICE account does not have sufficient privileges to read the IIS configuration settings. As such, you must either grant READ permissions to NETWORK SERVICE for the IIS configuration files, or configure the COM+ package to run as a user that has at least READ access to the files in the InetSrv\config folder.
      • By default, the NETWORK SERVICE account may not have WRITE permission to the folder where your files are uploaded, so the checksum files cannot be written. As such, you will need to grant READ/WRITE access to the destination where the checksum files will be written.
    • The above steps are not generally recommended practices; but if you choose to grant NETWORK SERVICE permission to the configuration files, the remarks section in the code sample provides the details that you need.
    • Alternatively, you could skip the path lookup and always store the checksum files in a known location. This allows you to remove the MapSiteRootPath() and FindElement() methods from the code sample, and you need only grant the NETWORK SERVICE account permission for the known location.
  • The MapSiteRootPath() method in the provider sample calculates the path of the site's root, then uses the relative path of the uploaded file to compute the full path to the checksum file. This does not take into account any paths that include virtual directories; as such, you would need to accommodate for any virtual paths in your site's hierarchy. (That's too much code for this blog post.)
  • The provider defines a 1 GB constant for the maximum file size for computing checksums. I specified this value so that large files would not tie up your system's resources. You can increase or decrease that value, you could make that a parameter that is stored in the provider's settings, or you can remove the functionality completely. This provider runs synchronously, so larger files will obviously take more time. While it's outside the scope of this blog, you could implement some form of asynchronous functionality. (When discussing this provider with Daniel Vasquez Lopez, he suggested using MSMQ - but that's really going way beyond the scope of what I wanted to accomplish with this blog.)

All of that being said, this provider follows the same development path as the provider in my How to Use Managed Code (C#) to Create a Simple FTP Logging Provider walkthrough, so if you follow the steps in that walkthrough and substitute "FtpUploadChecksumDemo" every place that you see "FtpLoggingDemo" and add a reference to Microsoft.Web.Administration, you should have all of the steps that you need in order to use this provider.

So without further discussion, here's the code for the provider:

using System;
using System.Configuration.Provider;
using System.IO;
using System.Security.Cryptography;
using System.Text;
using Microsoft.Web.Administration;
using Microsoft.Web.FtpServer;

// NOTE: This code is provided "as-is" and comes with the following security
// considerations. The FTP service will host the compiled assembly in the
// "Microsoft FTP Service Extensibility Host" COM+ package (DLLHOST.EXE),
// which runs by default as NETWORK SERVICE. By default, this account does not
// have sufficient privileges to read the IIS configuration settings. As such,
// you must either grant READ permissions to NETWORK SERVICE for the configuration
// files, or configure the COM+ package to run as a user that has at least READ
// access to the files in the InetSrv\config folder and READ/WRITE access to the
// destination where the checksum file will be written. However, these are not
// generally recommended practices.
//
// If you choose to grant NETWORK SERVICE permission to the configuration files,
// the following three commands should accomplish the requisite permissions:
//
//  cacls "%SystemRoot%\System32\inetsrv\config" /G "Network Service":R /E
//  cacls "%SystemRoot%\System32\inetsrv\config\redirection.config" /G "Network Service":R /E
//  cacls "%SystemRoot%\System32\inetsrv\config\applicationHost.config" /G "Network Service":R /E
//
// NOTE: You will need to do something similar for your content directory so that
// the checksum files can be created.

public sealed class FtpUploadChecksumDemo : BaseProvider, IFtpLogProvider
{
  // Implement the logging method.
  void IFtpLogProvider.Log(FtpLogEntry loggingParameters)
  {
    // Test for a successful file upload operation.
    if ((loggingParameters.Command == "STOR") && 
      (loggingParameters.FtpStatus == 226))
    {
      try
      {
        // Define a 1GB maximum length - to prevent system hogging.
        const long maxLength = 0x3fffffff;

        // Map the path to the site root.
        string fullPath = MapSiteRootPath(loggingParameters.SiteName);
        // Append the relative path of the uploaded file.
        fullPath += loggingParameters.FullPath;
        // Expand any environment variables.
        fullPath = Environment.ExpandEnvironmentVariables(fullPath);
        // Convert forward slashes to back slashes
        fullPath = fullPath.Replace(@"/", @"\");

        // Open the uploaded file to create a CRC.
        using (FileStream input = File.Open(
          fullPath,
          FileMode.Open,
          FileAccess.Read,
          FileShare.Read))
        {
          // Test the input file length.
          if (input.Length > maxLength)
          {
            // Throw an execption if the file is too big.
            throw new ProviderException(
              String.Format("Input file is too large: {0}",
              input.Length.ToString()));
          }
          else
          {
            // Open the hash file for output.
            using (StreamWriter output = new StreamWriter(
              fullPath + ".MD5.txt",
              false))
            {
              // Create an MD5 object.
              MD5 md5 = MD5.Create();
              // Retrieve the hash byte array.
              byte[] byteArray = md5.ComputeHash(input);
              // Create a new string builder for the ASCII hash string.
              StringBuilder stringBuilder =
                new StringBuilder(byteArray.Length * 2);
              // Loop through the hash.
              foreach (byte byteMember in byteArray)
              {
                // Append each ASCII hex byte to the hash string.
                stringBuilder.AppendFormat("{0:x2}", byteMember);
              }
              // Write the hash string to the output file.
              output.Write(stringBuilder);
            }
          }
        }
      }
      catch(Exception ex)
      {
        throw new ProviderException(ex.Message);
      }
    }
  }

  // This method is almost 100% from scripts that were created
  // by the IIS Manager Configuration Editor admin pack tool.
  private static string MapSiteRootPath(string siteName)
  {
    try
    {
      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", siteName);
        if (siteElement == null)
        {
          throw new InvalidOperationException("Element not found!");
        }
        else
        {
          ConfigurationElementCollection siteCollection =
            siteElement.GetCollection();
          ConfigurationElement applicationElement =
            FindElement(siteCollection,
            "application",
            "path", @"/");
          if (applicationElement == null)
          {
            throw new InvalidOperationException("Element not found!");
          }
          else
          {
            ConfigurationElementCollection applicationCollection =
              applicationElement.GetCollection();
            ConfigurationElement virtualDirectoryElement =
              FindElement(applicationCollection,
              "virtualDirectory",
              "path", @"/");
            if (virtualDirectoryElement == null)
            {
              throw new InvalidOperationException("Element not found!");
            }
            else
            {
              return virtualDirectoryElement["physicalPath"].ToString();
            }
          }
        }
      }
    }
    catch (Exception ex)
    {
      throw new ProviderException(ex.Message);
    }
  }

  // This method is almost 100% from scripts that were created
  // by the IIS Manager Configuration Editor admin pack tool.
  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;
  }
}

That wraps it up for today's post.

Note: This blog was originally posted at http://blogs.msdn.com/robert_mcmurray/

A Little Scripting Saved My Day (;-])

I have mentioned in previous blog posts that I tend to write many of my blog posts and walkthroughs for IIS.NET based on code that I've written for myself, and today's blog post is the story of how one of my samples saved my rear over this past weekend.

One of the servers that I manage is used to host web sites for several friends of mine. (It's their hobby to have a web site and it's my hobby to host it for them.) Anyway, sometime on Sunday someone let me know that one of my sites didn't seem to be behaving correctly, so I browsed it with Internet Explorer and saw that I was getting an HTTP 503 error. I've seen this error when an application pool goes offline for some reason, so I didn't panic - yet - because I knew that the web site was in a separate application pool. With that in mind, I browsed to a web site that is in a different application pool. Same thing - HTTP 503 error. This was beginning to concern me.

I logged into the web server and ran iisreset from a command-line - this threw the following error - and now I was really starting to become agitated:

CMD>iisreset

Attempting stop...
Internet services successfully stopped
Attempting start...
Restart attempt failed.
The IIS Admin Service or the World Wide Web Publishing Service, or a service dependent on them failed to start. The service, or dependent services, may had an error during its startup or may be disabled.

CMD>

I knew that the cause of the error should be in the Windows Event Viewer, so I opened the System log in Event Viewer and saw the following error:

Log Name: System
Source: Microsoft-Windows-WAS
Date: 7/26/2009 10:59:52 AM
Event ID: 5172
Task Category: None
Level: Error
Keywords: Classic
User: N/A
Computer: MYSERVER
Description: The Windows Process Activation Service encountered an error trying to read configuration data from file '\\?\C:\Windows\system32\inetsrv\config\applicationHost.config', line number '308'. The error message is: 'Configuration file is not well-formed XML'. The data field contains the error number.
Event Xml:

<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="Microsoft-Windows-WAS" Guid="{4E616D65-6F6E-6D65-6973-526F62657274}" EventSourceName="WAS" />
    <EventID Qualifiers="49152">5172</EventID>
    <Version>0</Version>
    <Level>2</Level>
    <Task>0</Task>
    <Opcode>0</Opcode>
    <Keywords>0x80000000000000</Keywords>
    <TimeCreated SystemTime="2009-07-26T17:59:52.000Z" />
    <EventRecordID>32807</EventRecordID>
    <Correlation />
    <Execution ProcessID="0" ThreadID="0" />
    <Channel>System</Channel>
    <Computer>MYSERVER</Computer>
    <Security />
  </System>
  <EventData>
    <Data Name="File">\\?\C:\Windows\system32\inetsrv\config\applicationHost.config</Data>
    <Data Name="LineNumber">308</Data>
    <Data Name="Error">Configuration file is not well-formed XML</Data>
    <Binary>0D000780</Binary>
  </EventData>
</Event>

Now that I was armed with the file name and line number of the failure in my configuration settings, I was able to go straight to the source of the problem. (I love IIS 7's descriptive error messages - don't you?) Once I opened the file and jumped to the correct location, I saw several lines of unintelligible garbage. For reasons that are still unknown to me - my applicationHost.config file had become corrupted and IIS was dead in the water until I fixed the problem. I looked through the file and removed most of the garbage and saved the edited file to IIS - this got the web sites working, but only partially. Some necessary settings had obviously been removed while I was clearing all of out the unintelligible garbage, and it might take me a long time to discover what those settings were.

The next thing that I did was to take a look in my two readily-accessible backup drives; I have two external hard drives that keep a backup of the web server - one hard drive is directly plugged into the web server via a USB cable, and the other hard drive is plugged into a physically separate server that rotates drives with off-site storage on a monthly basis. The problem is, my weekly backups had just run, so the copy in each backup location had been overwritten with the corrupted version. (I'm going to have to rethink my backup strategy after this - but that's another story.) The backup copy in my off-site storage location should be intact, but that copy would be a few weeks old so I would be missing some settings, and I would have to drive an hour or so round-trip in order to pick up the drive. This wasn't an ideal solution - but it was definitely a feasible strategy.

It was at this point that I remembered that I had written following blog post some time ago:

I wrote the script in that blog post for the server that I was currently managing, and because of this preventative measure I had dozens of backups going back several weeks to choose from. So I was able to quickly find a copy with no corruption and I restored that copy to my IIS config directory. At this point all of my web sites came online with all of their functionality. Having fixed the major issues, I used WinDiff to verify any settings that might have been changed between the restored copy and the corrupted copy.

So in conclusion, this story had a happy ending, and it left me with a few lessons learned:

  • You can never have too many backups
  • I need to rethink how I roll out my backup strategy with regard to using external hard drives
  • Writing cool scripts to automate your backups can save your rear end

That sums it up for today's post. Open-mouthed smile

Note: This blog was originally posted at http://blogs.msdn.com/robert_mcmurray/

Merging FTP Extensibility Walkthroughs

Over the past several months I’ve been publishing a series of walkthroughs that use the extensibility in FTP 7.5 to create a several custom providers for a variety of scenarios, and today I posted my most recent entry in the series:

How to Use Managed Code to Create an FTP Authentication Provider using an XML Database

As a piece of behind-the-scenes trivia, some of these walkthroughs were based off custom providers that I had actually written for my FTP servers, and I used the samples that I wrote for some of the other walkthroughs as a starting point for custom providers that I currently use. With that in mind, I’d like to use today’s blog to talk about some of the ways that I combine what you see in a few of these walkthroughs into some useful scenarios.

One of the common providers that I use is a combination of the code that you see in these two walkthroughs:

Here's the way that I create the provider - I start with a single provider class that implements the IFtpHomeDirectoryProvider, IFtpAuthenticationProvider, and IFtpRoleProvider interfaces, and I create a few global variables that I'll use later.

public class FtpXmlAuthentication : BaseProvider,
    IFtpHomeDirectoryProvider,
    IFtpAuthenticationProvider,
    IFtpRoleProvider
{
    private string _XmlFileName;

    private string _HomeDirectory;

    private Dictionary<string, XmlUserData> _XmlUserData =
        new Dictionary<string, XmlUserData>(
            StringComparer.InvariantCultureIgnoreCase);
}

I add an Initialize() method to the class, where I load the values named xmlFileName and homeDirectory from the configuration settings.

protected override void Initialize(StringDictionary config)
{
    _XmlFileName = config["xmlFileName"];
    _HomeDirectory = config["homeDirectory"];
    if (string.IsNullOrEmpty(_XmlFileName))
    {
        throw new ArgumentException("Missing xmlFileName value in configuration.");
    }
}

I recycle the provider across a bunch of different FTP sites, and I don't always use the custom home directory feature, so my GetUserHomeDirectoryData() method has to accommodate for that. (Note: this means that your FTP site has to use a method of User Isolation other than "Custom". You can find more information about User Isolation on the FTP User Isolation Page.)

string IFtpHomeDirectoryProvider.GetUserHomeDirectoryData(
    string sessionId,
    string siteName,
    string userName)
{
    if (string.IsNullOrEmpty(_HomeDirectory))
    {
        throw new ArgumentException("Missing homeDirectory value in configuration.");
    }
    return _HomeDirectory;
}

(Note: While it may seem that I could throw the ArgumentException() in the Initialize() method, since I don't always need this value for providers that don't implement the home directory lookup it's best to throw the exception in the GetUserHomeDirectoryData() method.)

The last thing that I do for the provider is to copy the AuthenticateUser(), IsUserInRole(), ReadXmlDataStore(), GetInnerText() methods and XmlUserData class from the How to Use Managed Code to Create an FTP Authentication Provider using an XML Database walkthrough. This gives me a custom FTP authentication provider that provides user, role, and home directory lookups. This means the XML file for the provider registration has to vary a little from the walkthroughs in order to define settings for the xmlFileName and homeDirectory values. Here's an example of that that might look like:

<system.ftpServer>
    <providerDefinitions>
        <add name="ContosoXmlAuthentication" type="FtpXmlAuthentication,FtpXmlAuthentication,version=1.0.0.0,Culture=neutral,PublicKeyToken=426f62526f636b73" />
        <activation>
            <providerData name="ContosoXmlAuthentication">
                <add key="xmlFileName" value="C:\Inetpub\www.contoso.com\Users.xml" />
                <add key="homeDirectory" value="C:\Inetpub\www.contoso.com\ftproot" />
            </providerData>
        </activation>
    </providerDefinitions>

    <!-- Other XML goes here -->

</system.ftpServer>

The last thing that you need to do is to create the XML file that contains the usernames and passwords, which you can copy from the How to Use Managed Code to Create an FTP Authentication Provider using an XML Database walkthrough.

I use this provider on multiple FTP sites, so I simply re-register the provider under a different name and specify different values for the xmlFileName and homeDirectory values:

<system.ftpServer>
    <providerDefinitions>
        <add name="ContosoXmlAuthentication" type="FtpXmlAuthentication,FtpXmlAuthentication,version=1.0.0.0,Culture=neutral,PublicKeyToken=426f62526f636b73" />
        <add name="FabrikamXmlAuthentication" type="FtpXmlAuthentication,FtpXmlAuthentication,version=1.0.0.0,Culture=neutral,PublicKeyToken=426f62526f636b73" />
        <add name="WingTipToysXmlAuthentication" type="FtpXmlAuthentication,FtpXmlAuthentication,version=1.0.0.0,Culture=neutral,PublicKeyToken=426f62526f636b73" />
        <activation>
            <providerData name="ContosoXmlAuthentication">
                <add key="xmlFileName" value="C:\Inetpub\www.Contoso.com\Users.xml" />
                <add key="homeDirectory" value="C:\Inetpub\www.Contoso.com\ftproot" />
            </providerData>
            <providerData name="FabrikamXmlAuthentication">
                <add key="xmlFileName" value="C:\Inetpub\www.Fabrikam.com\Users.xml" />
                <add key="homeDirectory" value="C:\Inetpub\www.Fabrikam.com\ftproot" />
            </providerData>
            <providerData name="WingTipToysXmlAuthentication">
                <add key="xmlFileName" value="C:\Inetpub\www.WingTipToys.com\Users.xml" />
                <add key="homeDirectory" value="C:\Inetpub\www.WingTipToys.com\ftproot" />
            </providerData>
        </activation>
    </providerDefinitions>

    <!-- Other XML goes here -->

</system.ftpServer>

So in the end I have a provider that provides unique users, roles, and home directory for each FTP site. I point the FTP root to a path that is outside of the HTTP root, so my users can upload files for an application like a photo gallery that I provide them, but they can't access the actual ASP.NET files for the application. Since they're using accounts from the XML file, I don't have to hand out physical accounts on my servers or my domain. (The security-paranoid side of my personality really likes that.)

For some sites I use the XML file for ASP.NET membership by following the instructions in the How to use the Sample Read-Only XML Membership and Role Providers with IIS 7.0 walkthrough. In those cases, I move the XML file into the App_Data folder of the web site. Once again, since the FTP root is different than the HTTP root, this prevents any of my FTP users from accessing the XML file and making changes to it. (Although you could do that if you wanted to allow one of your users to update the list of FTP users for their site. But as you can imagine, the security-paranoid side of my personality really does not like that.)

All that being said, I hope that this helps you to get an idea for other ways that you can use some of the walkthroughs that I've been writing. I have several additional providers and walkthroughs that I’m working on for the IIS.NET web site, but I’ll keep those as a secret for now. ;-]

Note: This blog was originally posted at http://blogs.msdn.com/robert_mcmurray/

FTP Clients - Part 6: Core FTP LE

For this installment in my series about FTP Clients, I'd like to take a look at the Core FTP client. For this blog post I used Core FTP Lite Edition (LE) version 1.3c (build 1447) and version 2.1 (build 1603), although all of my screen shots are from version 2.1. Core FTP is available from the following URL:

http://www.coreftp.com/

At the time of this blog post, Core FTP provides the LE for free and charges a small fee for a professional version.

Like most graphical FTP clients, the Core FTP LE user interface is pretty easy to use and rather straight-forward - you have separate windows for your local and remote files/folders, as well as a logging window that lists the FTP commands that are sent and the FTP server's responses:

Core FTP LE has a great Site Manager feature, which allows you to store commonly-used connections to FTP sites:

Clicking on the Advanced button gives you a great deal of additional configuration settings, and I'll say more about that later:

Command-Line Support

This is one of my favorite Core FTP LE features: command-line support. Yes - I'm a geek - and I like being able to script things and run batch jobs to automate whatever I can, so command-line support is always a plus for me. That said, the interface for the Core FTP LE command-line client is not an interactive experience like you get with the built-in Windows FTP.EXE or MOVEit Freely command-line clients. The Core FTP LE command-line client is provided as via the Corecmd.exe file that is installed in the main the Core FTP LE application directory, and is used for a single FTP operation like GET or PUT - although you can pass the name of a script file to execute several commands before/after logging in or before/after a file transfer.

So my final judgment is that the Core FTP LE client doesn't have great command-line support, but it's still really nice to have.

Using FTP over SSL (FTPS)

The Core FTP LE client supports both Implicit and Explicit FTPS, so the choice is up to you which method to use. When creating a connection to a server, Core FTP LE has three FTP options that you can use with FTP7:

  • AUTH SSL
  • AUTH TLS
  • FTPS (SSL DIRECT)

It's important to choose this option correctly, otherwise you will run into problems when trying access a site using FTPS. If you'll recall from my "FTP Clients - Part 2: Explicit FTPS versus Implicit FTPS" and my other FTP client blog posts, Explicit FTPS allows the client to initiate SSL/TLS whenever it wants, but for most FTP clients that will be when logging in to your FTP site, and in that regard it may almost seem like Implicit FTPS, but behind the scenes the FTP client and server are communicating differently.

In the case of FTP7, the following rules apply:

  • If you enable FTPS in FTP7 and you assign the FTP site to port 990, you are using Implicit FTPS - Core FTP LE refers to this as FTPS (SSL DIRECT). (Note: make sure that you configure your FTP client to connect on port 990.)
  • If you enable FTPS in FTP7 and you assign the FTP site to any port other than port 990, you are using Explicit FTPS - Core FTP LE allows you to configure your connection to use AUTH SSL or AUTH TLS for the explicit connection.

The type of FTPS is specified on the Connection drop-down menu:

Once you have chosen an FTPS connection, the Core FTP LE client offers you additional options where you can customize which parts of the session will be encrypted:

You can combine the Core FTP SSL options with the advanced SSL policies for your FTP7 sites to customize your security level:

Using FTP Virtual Hosts

Because Core FTP LE's site manager allows you to specify the virtual host name as part of the user credentials, Core FTP LE works great with FTP7's virtual host names. All that you need to do is use the "ftp.example.com|username" syntax when specifying your username, and when you connect to the FTP7 server it will route your requests to the correct FTP virtual host site.

Using True FTP Hosts

A really great feature of Core FTP LE is the ability to send pre-login commands, and since this feature allows you to enter custom commands you can specify the actual FTP HOST command as part of your login:

This is a tremendous feature if you're hosting multiple FTP sites on the same IP address, and gives Core FTP LE some of the best support for true FTP HOSTs.

Scorecard for Core FTP LE

That wraps it up for our quick round-trip for some of Core FTP LE's features, and here's the scorecard results:

Client NameDirectory
Browsing
Explicit
FTPS
Implicit
FTPS
Virtual
Hosts
True
HOSTs
Core FTP LE 1.3 Rich Y Y Y Y 1
Core FTP LE 2.1 Rich Y Y Y Y 1
1 As noted earlier, true FTP HOSTs are available in Site Manager using pre-login commands.

Note: Keeping with my standard disclaimer, there are a great number of additional features that Core FTP LE provides - and I just focused on the topic areas that apply to FTP7.

Note: This blog was originally posted at http://blogs.msdn.com/robert_mcmurray/

FTP 7.5 Service Extensibility References

As I pointed out in my recent blog post that was titled "FTP 7.5 and WebDAV 7.5 have been released", one of the great new features of the FTP 7.5 service is extensibility. In that blog post I mentioned that I wrote the following walkthroughs to help developers get started writing providers for the FTP 7.5 service, and these walkthroughs are all available on Microsoft's learn.iis.net Web site:

We have also recently published the FTP Service Extensibility Reference on Microsoft's MSDN Web site, and here is a list of all the reference topics that we have written for FTP 7.5 service extensibility:

I hope this helps!

Note: This blog was originally posted at http://blogs.msdn.com/robert_mcmurray/

Advertising IIS Around the World

In case you haven't already surmised from some of my other blog posts, I've been around IIS for a long time, so it should go without saying that I'm a big fan of IIS.

I remember when we first released IIS 1.0 for Windows NT 3.51 and we were handing out IIS CD-ROMs at trade shows way back in early 1996; everyone kept asking, "What is this for?" (Obviously the Internet was still a new concept to a lot of people back then.) Out of nostalgia, I kept a shrink-wrapped copy of IIS 1.0 for myself, and I think that I have one of the few boxes left. It usually sits in my office next to my IIS 4.0 Limited Edition CD-ROM...

IIS-1.0-BoxIIS-4.0-CD-ROM

Anyway, over the years the IIS team has printed up an assortment of IIS shirts, and I have been wearing several of these various IIS shirts as I have travelled around the world. Because I have been doing so for some time, I've found myself advertising IIS in some unexpected places. For example, my wife and I were visiting our daughter in Peru this past March, and we took the following photograph of my daughter and me (wearing one of my IIS shirts) at Machu Picchu:

IIS-at-Machu-Picchu

So - you may ask, "What does IIS have to do with one of the newest wonders of the world?" My answer is, "Um... nothing, really." I happened to be wearing my IIS shirt that day, and it made a pretty good photo. (Obviously, it was a bad hair day for me... so I'm blaming the mountain winds. ;-] )

As another example, my son and I took a road trip down the California coast this past summer to visit my brother in San Francisco, and we posed for the following photo before boarding the boat to Alcatraz:

IIS-at-Alcatraz

There are other times where I have taken advantage of a situation to deliberately and shamelessly pose for IIS. For example, I was scuba diving in Hawaii a couple of years ago, and I borrowed someone's dive slate to write the following message:

IIS-7-Rocks

Actually, I tend to wear IIS shirts when I go scuba diving as a matter of habit - it's kind of a good luck charm for me - and this behavior of mine has led to some interesting experiences.

For example, my wife and I were going scuba diving in the Bahamas several years ago, and once again I was wearing one of my IIS t-shirts that day. The dive company had sent a van to our hotel to pick up several divers, and as I climbed aboard, one of the other passengers saw my shirt and remarked, "Oh, we have an IIS person today. I'm more of an Apache Girl myself." I quickly replied, "That's okay, everybody needs a hobby." I really only expected her to get the joke, but apparently we had a tech-savvy group that day because everyone else on the bus chimed in with, "Ooooooh - you're in trouble." I didn't realize what everyone meant until we got to the dive boat where Apache Girl came walking up to me holding an air tank and said, "I'm your dive guide today, and I picked this air tank especially for you." We both had a good laugh, and I survived the dive so she can thankfully take a joke.

IIS-in-the-Bahamas

All that being said, I really like to show off IIS. It's a lot of fun to demonstrate the many features of IIS to customers at trade shows, and it's a lot of fun to unofficially advertise IIS when I'm traveling on vacation in various places around the world. So if you see me when I'm on vacation somewhere, the chances are good that you'll be able to find me in a crowd - because I'll be the geek wearing the IIS shirt.

Note: This blog was originally posted at http://blogs.msdn.com/robert_mcmurray/

FrontPage Macro: Fix Filenames

Using this FrontPage VBA Macro

This FrontPage VBA Macro is designed to fix potential filename problems by:

  • Converting all filenames to lowercase.
  • Converting all non-alphanumeric characters to underscore characters.
  • Removing duplicate underscore characters.

FrontPage VBA Macro Example Code

Public Sub FixFilenames()
Dim objWebFile As WebFile
Dim objWebFolder As WebFolder
Dim strOldFile As String
Dim strNewFile As String

If Len(Application.ActiveWeb.Title) = 0 Then
MsgBox "A web must be open." & vbCrLf & vbCrLf & "Aborting.", vbCritical
Exit Sub
End If

For Each objWebFolder In Application.ActiveWeb.AllFolders
Here:
For Each objWebFile In objWebFolder.Files
strOldFile = objWebFile.Name
strNewFile = FixName(strOldFile)
If strNewFile <> strOldFile Then
objWebFile.Move objWebFolder.Url & "/" & strNewFile & _
".tmp.xyz." & objWebFile.Extension, True, False
objWebFile.Move objWebFolder.Url & "/" & strNewFile, True, False
GoTo Here
End If
Next
Next

MsgBox "Finished!"

End Sub

Private Function FixName(ByVal tmpOldName As String) As String
Dim intChar As Integer
Dim strChar As String
Dim tmpNewName As String

Const strValid = "1234567890_-.abcdefghijklmnopqrstuvwxyz"

tmpOldName = LCase(tmpOldName)

For intChar = 1 To Len(tmpOldName)
strChar = Mid(tmpOldName, intChar, 1)
If InStr(strValid, strChar) Then
tmpNewName = tmpNewName & strChar
Else
tmpNewName = tmpNewName & "_"
End If
Next

Do While InStr(tmpNewName, "__")
tmpNewName = Replace(tmpNewName, "__", "_")
Loop

Do While InStr(tmpNewName, "_-_")
tmpNewName = Replace(tmpNewName, "_-_", "_")
Loop

FixName = tmpNewName

End Function

FTP Clients - Part 5: MOVEit Freely Command-Line Secure FTP Client

For this installment in my series about FTP Clients, I'd like to take a look at the MOVEit Freely Command-Line Secure FTP Client ("FTPS.EXE") from Ipswitch. For this blog post I used MOVEit Freely FTP Client version 5.0.0.0, and it is available from one of the following URLs:

http://www.ipswitchft.com/products/moveit/client/freely/

http://www.ipswitchft.com/Products/MOVEitFreely/

At the time of this blog post, Ipswitch is providing the MOVEit Freely FTP client for free, although you are required to fill out a registration page with a short questionnaire. For more information on the license for the MOVEit Freely command-line FTP client, please see Ipswitch's web site.

If you're like me and you like to script a lot of batch jobs on your servers, the MOVEit Freely command-line FTP client can be quite handy. The command set for the MOVEit Freely FTP client is a greatly-enhanced superset of the commands that are available with the command-line FTP.EXE client that is built-in to Windows, with added features that make additional functionality possible, such as SSL, passive FTP, resumable downloads, etc. There is a manual available with the MOVEit Freely FTP client, and I highly recommend using the manual as a reference when writing automation scripts because there are a lot of options that are available to you.

Active and Passive FTP

One of the great things about the MOVEit Freely command-line FTP client is the ability to use either Passive or Active connections, and you can switch between the two connection types using the "passive" command in the FTP session. This helps immensely when working with firewalls and such. The following example shows what that might look like:

CMD>ftps.exe ftp.example.com

220 Microsoft FTP Service
Connected to ftp.example.com.
User: administrator
331 Password required for administrator.
Password: ********
230 User logged in.
ftp> passive
Passive mode  On .
ftp> put foobar.txt
227 Entering Passive Mode (192,168,0,1,224,39).
150 Opening ASCII mode data connection.
226 Transfer complete.
ftp: 8 bytes sent in 0.06Seconds 0.13Kbytes/sec.
ftp> passive
Passive mode  Off .
ftp> put foobar.txt
200 PORT command successful.
125 Data connection already open; Transfer starting.
226 Transfer complete.
ftp: 8 bytes sent in 0.01Seconds 0.78Kbytes/sec.
ftp> bye
221 Goodbye.

CMD>

Using FTP over SSL (FTPS)

The MOVEit Freely command-line FTP client supports both Implicit and Explicit FTPS, so the choice is up to you which one to use, but I generally use Explicit FTPS since Implicit FTPS should be considered obsolete. The SSL mode is specified using the "-e:" parameter on the command-line, and the 5.0.0.0 version of the MOVEit Freely command-line FTP supports the following values for that parameter:

ParameterFTPS ModeDescription
off n/a Specifies that no encryption will be used on either the control channel or data channel.

Note: This is the default behavior.

on Explicit Specifies that both the control channel and data channel will use encryption over an explicit FTPS connection.

Notes:

  • This uses the AUTH TLS, PBSZ 0, and PROT P commands when establishing a connection.
  • You can use "prot on" and "prot off" to specify whether encryption will be used. (See Note 1 below.)
on-ccc Explicit Specifies the control channel will use encryption over an explicit FTPS connection during login, but the control channel will switch to unencrypted after a login has been established. Data channel connections will still be encrypted.

Notes:

  • This uses the AUTH TLS, PBSZ 0, and PROT P commands to enable encryption when establishing a connection, then uses the CCC command after the username and password are successfully negotiated. (See Note 2 below.)
  • The USER and PASS commands are the only commands that will be encrypted; all other FTP commands are unencrypted.
tls-p Explicit Specifies that both control and data channel will use encryption over an explicit FTPS connection.

Notes:

  • This uses the AUTH TLS and PROT P commands when establishing a connection.
  • You can use "prot on" and "prot off" to specify whether encryption will be used. (See Note 3 below.)
tls-c Explicit Specifies that only the control connection will use encryption over an explicit FTPS connection. Data channel connections will be unencrypted.

Notes:

  • This uses only the AUTH TLS to enable encryption when establishing a connection.
  • You must manually send a PBSZ command before you can use the "prot on" and "prot off" to specify whether encryption will be used. (See Note 1 and Note 3 below.)
tls-c-ccc Explicit Specifies that only the control connection will use encryption over an explicit FTPS connection during login, but the control channel will switch to unencrypted after a login has been established. Data connections will be unencrypted.

Notes:

  • This uses only the AUTH TLS to enable encryption when establishing a connection, then uses the CCC command after the username and password are successfully negotiated.
  • The USER and PASS commands are the only commands that will be encrypted; all other FTP commands are unencrypted.
implicit Implicit Specifies that both the control channel and data channel will use encryption over an implicit FTPS connection, which can only be on port 990 for the FTP7 service.

Notes:

  • The implicit FTPS connection will encrypt both the control channel and data channel without the use of an AUTH command.
  • You can use "prot on" and "prot off" to specify whether encryption will be used. (See Note 3 below.)
implicit-ccc Implicit Specifies that the control channel would use encryption over an implicit FTPS connection during login and switch the control channel to unencrypted after login, but this is not supported in FTP7. The implicit FTPS connection will succeed, but the FTP7 service will return an error when the CCC command is sent. You can ignore the error and continue to use the session.

Notes:

  • Implicit FTPS connections require encryption for the command channel. (See Note 4 below.)
  • You can use "prot on" and "prot off" to specify whether encryption will be used. (See Note 3 below.)

The following notes should be considered:

  1. Encryption of the data connection can be changed during the session with MOVEit Freely's "prot" command. You can use the "prot on" to specify that data connections will be encrypted, and "prot off" to specify that data connections will be unencrypted; these commands will respectively send the PROT P and PROT C commands over FTP.
  2. The "on-ccc", "tls-c-ccc", and "implicit-ccc" parameters are useful with firewalls that inspect FTP traffic. Switching the control channel back to unencrypted allows the firewall to inspect and possibly modify the FTP commands. For example, firewalls that are performing Network Address Translation (NAT) may need to modify the PORT and PASV commands.
  3. "RFC 2228 - FTP Security Extensions" states that FTP clients are required to send an FTP PBSZ command before sending an FTP PROT command, and unfortunately the MOVEit Freely 5.0.0.0 FTP client does not send this command, so you get a "503 Bad sequence of commands" error. You can work around this by issuing a literal command to the server using the FTP client's "quote" command, which appears to work. See the following example for more information. The following example shows what that might look like:
    Note: I turned on debugging for this example with the "-d" option so you can see the sequence of commands.
    CMD>ftps.exe -e:tls-c -d ftp.example.com
    
    220 Microsoft FTP Service
    ---> AUTH TLS
    234 AUTH command ok. Expecting TLS Negotiation.
    Connected to ftp.example.com.
    User: administrator
    ---> USER administrator
    331 Password required for administrator.
    Password: ********
    ---> PASS (hidden)
    230 User logged in.
    ---> SYST
    215 Windows_NT
    ftp> prot on
    ---> PROT P
    503 Bad sequence of commands.
    Data connections will still NOT be encrypted
    ftp> quot PBSZ 0
    ---> PBSZ 0
    200 PBSZ command successful.
    ftp> prot on
    ---> PROT P
    200 PROT command successful.
    Data connections will be encrypted
    ftp> bye
    ---> QUIT
    221 Goodbye.
    
    CMD>
  4. The FTP7 service treats implicit FTPS connections as though the SSL policy for the control is set to "Require".

One last note about FTPS, if you are using a certificate with trust issues, you will see the following prompt displayed:

You can get around this certificate prompt when writing scripts by using the "-z" switch. The following example shows what that might look like:

Note: For this example I bypassed a certificate prompt with the "-z" switch, and I specified passive FTP with the "passive" command.
CMD>ftps.exe -z -e:on ftp.example.com

220 Microsoft FTP Service
234 AUTH command ok. Expecting TLS Negotiation.
Connected to ftp.example.com.
User: administrator
331 Password required for administrator.
Password: ********
230 User logged in.
200 PBSZ command successful.
200 PROT command successful.
215 Windows_NT
ftp> passive
Passive mode On .
ftp> ls -l
227 Entering Passive Mode (192,168,0,1,224,97).
150 Opening ASCII mode data connection.
03-10-08 10:41AM <DIR> App_Data
09-04-08 11:41AM <DIR> aspnet_client
09-04-08 11:41AM <DIR> bin
12-17-02 11:47AM 2360 default.aspx
ftp: 128 bytes received in 0.03Seconds 83.25Kbytes/sec.
226 Transfer complete.
ftp> bye
221 Goodbye.

CMD>

Using FTP Virtual Hosts

Since everything is happening from a command-line, you can use both FTP7's Virtual Hosts and the actual FTP HOST command. Once again, see my Virtual Hosts and Host Names in FTP7 blog post for more information about FTP Virtual Host Names and FTP True Host Names, and see https://datatracker.ietf.org/drafts/draft-hethmon-mcmurray-ftp-hosts/ for more information about status of the FTP HOST command.

In any event, FTP7 virtual hosts are supported by using the "ftp.example.com|username" syntax when specifying your username, and when you connect to the FTP7 server it will route your requests to the correct FTP virtual host site. The following example shows what that might look like:

CMD>ftps.exe ftp.example.com

220 Microsoft FTP Service
Connected to ftp.example.com.
User: ftp.contoso.com|administrator
331 Password required for ftp.contoso.com|administrator.
Password: ********
230-Directory has 104,857,600 bytes of disk space available.
230 User logged in.
ftp> bye
221 Goodbye.

CMD>

True FTP hosts can be used by specifying the FTP HOST command before the client sends the USER and PASS credentials. This is accomplished in two parts:

  1. You need to suppress the automatic username prompt MOVEit client by using the "-n" switch on the command-line.
  2. You need to specify the host name using the MOVEit client's "quote" command, which allows you to send custom FTP commands. The syntax for this would be "quote HOST ftp.example.com".

The following example shows what that might look like:

CMD>ftps.exe -n ftp.example.com

220 Microsoft FTP Service
Connected to ftp.example.com.
ftp> quote HOST ftp.contoso.com
220 Host accepted.
ftp> USER administrator
331 Password required for administrator.
Password: ********
230-Directory has 104,857,600 bytes of disk space available.
230 User logged in.
ftp> bye
221 Goodbye.

CMD>

Scorecard for the MOVEit Freely command-line FTP client

This concludes our quick look at some of the features that are available with the MOVEit Freely command-line FTP client, and here's the scorecard results:

Client NameDirectory
Browsing
Explicit
FTPS
Implicit
FTPS
Virtual
Hosts
True
HOSTs
MOVEit Freely 5.0.0.0 n/a Y Y Y Y 1
1 As noted earlier, true FTP HOSTs are available when using the "quote HOST ftp.example.com" syntax.

Note: Keeping with my standard disclaimer, there are a great number of additional features that the MOVEit Freely command-line FTP client provides - I'm just keeping the focus on those topic areas that apply to FTP7.

Note: This blog was originally posted at http://blogs.msdn.com/robert_mcmurray/

Batch File: Delete Duplicate Files

Using this Batch File

Some time ago a friend of mine gave me a bunch of JPG files, but for some reason she had two copies of every image in the collection. The names of the images had all been randomized, and since there were hundreds of files in the collection it would have taken hours to find and delete the duplicates. With that in mind, I wrote the following batch file that loops through the collection of files and does a binary comparison to find and delete duplicate files.

To use the example code, copy the batch file code from below into Notepad and save it as "_del_dupes.cmd" in the folder where you have duplicate files

Note: As with many utilities that I write - this is a destructive operation, meaning that it will delete files without prompting, so you should always make a backup just in case something goes terribly wrong... ;-]

Batch File Example Code

@echo off

dir *.jpg /b > _del_dupes.1.txt

for /f "delims=|" %%a in (_del_dupes.1.txt) do (
   if exist "%%a" (
      dir *.jpg /b > _del_dupes.2.txt
      for /f "delims=|" %%b in (_del_dupes.2.txt) do (
         if not "%%a"=="%%b" (
            echo Comparing "%%a" to "%%b"...
            fc /b "%%a" "%%b">NUL
            if errorlevel 1 (
               echo DIFFERENT
            ) else (
               echo SAME
               del "%%b"
            )
         ) 
      ) 
   )
)

del _del_dupes.?.txt

FTP Clients - Part 4: FileZilla

For this next installment in my FTP Clients series, I'd like to take a look at the FileZilla FTP client. For this blog post I was using FileZilla version 3.1.6.

There are a lot of places where you can find FileZilla, but the best location is the official FileZilla web site at http://filezilla-project.org/. The FileZilla FTP client is free, so you can't beat the price. ;-]

The user interface is pretty straight-forward: you have separate windows for your local and remote files/folders, as well as a logging window that lists the FTP commands that are sent and the FTP server's responses.

FileZilla has a great Site Manager feature, which allows you to store commonly-used connections to FTP sites.

Using FTP over SSL (FTPS)

When creating a connection to an FTPS server, FileZilla has two options: FTPS and FTPES. It's important to have this option configured correctly, otherwise you will run into problems when trying access a site using FTPS. If you'll recall from my "FTP Clients - Part 2: Explicit FTPS versus Implicit FTPS" blog post, Explicit FTPS allows the client to initiate SSL/TLS whenever it wants, but for most FTP clients that will be when logging in to your FTP site, and in that regard it may almost seem like Implicit FTPS, but behind the scenes the FTP client and server are communicating differently.

In the case of FTP7, the following rules apply:

  • If you enable FTPS and you assign the FTP site to port 990, you are using Implicit SSL - FileZilla refers to this as FTPS.
  • If you enable FTPS and you assign the FTP site to any port other than port 990, you are using Explicit SSL - FileZilla refers to this as FTPES.

Using FTP Virtual Hosts

Because FileZilla's site manager allows you to specify the virtual host name as part of the user credentials, FileZilla works great with FTP7's virtual host names. All that you need to do is use the "ftp.example.com|username" syntax when specifying your username, and when you connect to the FTP7 server it will route your requests to the correct FTP virtual host site.

Unfortunately, even though FileZilla allows you to send custom commands, you cannot send custom commands outside of an established FTP session, so you can't send the FTP HOST command as part of your login, therefore true FTP hosts are not supported.

Directory Browsing

Using MS-DOS or UNIX directory listings in FTP7 didn't have any impact on whether FileZilla could render directory listings, nor did configuring any of the other options such as four-digit years, etc. When I create FTP connections in FileZilla's site manager it defaults to auto-detecting the FTP server type, which makes the directory browsing behavior transparent to the client. (Behind the scenes FileZilla is sending an FTP SYST command, which allows FileZilla to detect the operating system.)

You can customize the server type in the advanced settings for your FTP connection, so you can match up your FTP7 directory listing options and the server type that FileZilla expects, but personally I have had no problems with auto-detection so I prefer to use that option.

On a side note, if you intentionally misconfigure FileZilla's server type settings, you can cause FileZilla to behave strangely. For example, choosing a VMS server type and configuring FTP7 to use MS-DOS directory listings will not work, but then again - I wouldn't expect that to work. ;-]

Scorecard for FileZilla

So - that concludes our quick round-trip for some of FileZilla's features, and here's the scorecard results:

Client NameDirectory
Browsing
Explicit
FTPS
Implicit
FTPS
Virtual
Hosts
True
HOSTs
FileZilla 3.1.6 Rich Y Y Y N

Note: As with all of the FTP clients in this blog series, there are a great number of additional features that FileZilla provides - I'm just keeping the focus on a few specific topic areas that apply to FTP7.

Note: This blog was originally posted at http://blogs.msdn.com/robert_mcmurray/