One of the customer reported that whenever he tries to send e-mail by using System.Net.Mail API they get the following error “System.Net.Mail.SmtpException error message: Command not implemented. The server response was: Command not Supported”

I had a look at the application. They built a Microsoft Visual Studio 2005 based application and tried to send e-mail by using the System.Net.Mail.SmtpClient class. They use the DeliveryMethod.Network method from the Microsoft .NET Framework 2.0. The application receive the following System.Net.Mail.SmtpException error message: Command not implemented. The server response was: Command not Supported.

During the investigation, we found that this problem occurs because the remote SMTP server does not support the SMTP extended Hello (EHLO) command. The exception occurs when the remote SMTP server returns the 502 reply code and the System.Net.Mail.SmtpClient class expects the 500 reply code.

To overcome this issue, Microsoft released a hot fix downloaded from http://code.msdn.microsoft.com/KB913616/Release/ProjectReleases.aspx?ReleaseId=789. Also you can refer the detailed Knowledge base article regarding this issue and hot fix.

After almost two years and involved the release of four Technical Previews, Zeyad announced the worldwide availability of the Open XML SDK 2.0 for Microsoft Office. The Open XML SDK plays an integral part in creating Office document solutions that work on the client or server. The Open XML SDK allows you to create, consume, and manipulate Open XML files without needing to automate Office client applications.

Download the Open XML SDK 2.0 for Microsoft Office:
This download provides strongly typed part and content classes for use with Office 2007 & Office 2010 Open XML documents. http://www.microsoft.com/downloads/details.aspx?FamilyID=c6e744e5-36e9-45f5-8d8c-331df206e0d0

Please note:

• Open XML SDK 2.0 is freely redistributable by any solution provider implementing the formats
• Office applications are not required to use the Open XML SDK 2.0, and no software purchase is required.
• Developers can freely use the Open XML SDK to build document processing solutions for Microsoft Office files and for other implementations of the IS29500 standard

If you want learn more about Open XML SDK, then i would recommend to try with Brian Jones related articles (a lot of real world scenarios/solutions that are built with the SDK). Apart from this, here is a summary of links that will help you learn more about the Open XML SDK:

• MSDN

  • Open XML Developer Center

    • This site is your one-stop shop for finding all information related to Open XML and the Open XML SDK
  • Office Developer Center
  • Office Visual-How-To sites
  • An overview of Open XML SDK 2.0 for Microsoft Office
  • Class Library References
  • Microsoft Office File Format Documents

• YouTube Videos

  • The Open XML SDK Productivity Tool
  • Using the Open XML SDK to add repeating data to a PowerPoint Deck
  • Programmatically embedding an Excel spreadsheet into a Word document
  • Leveraging the Power of Word Automation Services and the Open XML SDK
  • Document Assembly: Merging Excel, PowerPoint, and Word Content Together
  • Extending the Reach of Excel Services with the Open XML SDK
  • Open XML SDK + Office Services: Better Together
  • Add Custom UI to Word Documents with the Open XML SDK
  • Programmatically Embedding a PDF into a Word Document
  • Import SmartArt From Ppt To Word
  • Retrieve Word Content Based on Styles

• Forum & Blogs

  • http://openxmldeveloper.org/ - A place to learn and share more about Open XML Formats, news, information, and getting questions answered
  • http://social.msdn.microsoft.com/Forums/en-US/oxmlsdk - A discussion forum for developer topics related to the Open XML Format SDK
  • http://blogs.msdn.com/ericwhite/ - Eric White's blog that focuses on Open XML and SharePoint development. This blog contains a lot of rich information on the Open XML file formats as well as sample code related to the Open XML SDK

• Conference Presentations

  • Open XML SDK + Office Services Presentation at PDC
  • Deep Dive Open XML and the Open XML SDK Presentation at SPC

You can download the Update Rollup 3 (thanks, Greg for helping here) for Exchange Server 2007 SP2 (x86/x64). It resolves issues that were found in Exchange Server 2007 since the software was released. This update rollup is highly recommended for all Exchange Server 2007 customers.

Per MSExchangeteam.com, some highlights of the product improvements and critical bug fixes were “…

• We responded to some of the great feedback we get from the community including two issues posted to the Exchange TechNet Forums about our last rollup:  Outlook web access signatures lose their blank line above the signature & Item Retention Period "TimeSpan overflowed because the duration is too long."  
• A couple of painful deadlock issues are now prevented as noted in KBs  978517 and 979219.  
• Two Store crash scenarios were repaired; see KBs  978528  & 979520. 
• Several improvements for meeting request issues are also included in this rollup…”

Also per TechNet, the Update Rollup 3 for Exchange Server 2007 fixes the following issues:

You can try when you do programming with VB.Net and Outlook automation:

• When you start automation code by declaring object variables with a specific object type that represents the top-level object and then declaring any child objects you want to reference.
  

  Dim olApp  As Outlook.Application

  
  
• You then create an instance of the top-level object by using the Set statement and the New keyword.

Set olApp = New Outlook.Application

Please note: You need to understand that the New keyword can't be used to create a new instance of a child object.

• To create an instance of a child object, use the appropriate method of the parent object along with the Set statement.

Set MailMessage = olApp.CreateItem(olMailItem)



• At the end of the procedure, each object variable is destroyed by explicitly setting it equal to the Nothing keyword. If you do this, there is no need to use a Set statement to instantiate the object. However, this technique is not recommended because you have no control over when the object variable is created.
  
• In detail, if your code must test to see if an object exists by using a statement such as If olApp Is Nothing Then, this test will return True if you have created an instance of the object in the Dim statement. Additionally, you might not need to use an object except at the user's request.
  
• If you create an instance of the object by using New in the Dim statement, the object will be created even if it isn't used. To maintain control over when an object is created, don't use the New keyword in the Dim statement, and instantiate the object by using a Set statement at the point in your code where you must use the object.