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Getting Started with ASP Messaging

 

Ed Beck
Microsoft Developer Support Messaging Team

May 1998
Updated November 1998

Contents

Security Considerations
Application Considerations
Network Architecture
Your Decision Tree
Application Requirements
The Basics
Examples
Writing Your ASP
Troubleshooting and Debugging
Common MAPI Errors
References


This paper presents an overview of what you need to think about when designing a messaging application to be run from an Active Server Page (ASP). Since this paper is meant to be an overview, there are several references to other publications that contain more detailed information about the topic being covered. This article serves as an introduction to the considerations and technologies involved in messaging from the Web.

Security Considerations

Security must be one of your first considerations when designing a messaging application for use on an ASP. There are three major components to be taken into consideration: Windows NT® security, Internet Information Server (IIS) security, and Exchange Server security. These must be set up so that they do not conflict with each other. Depending on your network architecture, you will be able to make use of different security features.

Two excellent articles on the MSDN Library provided much of the background information for this section. They are "Implementing a Secure Site with ASP" by Paul Enfield and "Authentication and Security for Internet Developers" by Scott Stabbert. Parts of this article were directly copied from those papers.

Windows NT Security

This paper assumes that you are using Windows NT 4.0 Server with Service Pack 3 (SP3) on an NTFS formatted hard drive. This part of the article will discuss the basics of NTLM. How NTLM relates to IIS will be discussed in "IIS Security" below.

NTLM

NTLM stands for Windows NT LAN Manager because it was developed and originally used in Microsoft LAN Manager, one of Microsoft's earliest networking products. NTLM assumes that the user has logged onto a Windows NT network from a client and has been authenticated by a Domain Controller. A very important part of NTLM is that the user's password never goes over the network. Instead, when a client attempts to use a resource on a Windows NT Server, the following routine takes place:

  1. A resource is requested from a Windows NT Server (IIS).
  2. The NT Server needs to authenticate a user before the user is granted access to the resource.
  3. NT Server challenges the user requesting the resource. In this challenge, the server sends a random value to be encrypted.
  4. The user machine sends the domain name, user name, and the encrypted value to the NT Server. The value is encrypted through a combination of a hash generated by the user password and the random value sent from the server.
  5. NT Server receives this encrypted token and stores it for later use.
  6. NT Server sends the domain name, user name, and encrypted token received from the client, along with the original random value, to a domain controller.
  7. The domain controller uses its copy of the user's password hash and the random number as a key to encrypt a token using the information it gets from the NT Server.
  8. The domain controller compares the token it generated with the one it received from the NT Server to make sure they match.
  9. If the tokens match, the user is granted access to the resource in question.

IIS Security

IIS is just a tool to provide files to browsers. Every time you request a file from a Windows NT machine, a security check occurs. Therefore, IIS must implement some way of providing files to:

  • Domain users (intranet).
  • Users who do not have a Windows NT domain account (Internet).

In the case of providing files to a Domain user, the process outlined above in the NTLM section could provide files to the user. But if you want to provide files to users who do not have a domain account, you need an account that is accessible from the Internet and will grant access to Internet users. IIS uses three authentication methods: Anonymous, NTLM, and Basic.

Anonymous

The way to provide access to nondomain users is that IIS sets up an account such that any user who hits a Web page is logged into an account that can access the Web. Whether or not you as the network administrator choose to use this account is up to you. You can decide to not allow anonymous access to your Web, or you can decide to create your own account to allow users anonymous access.

The Internet Service Manager allows you to change the authentication options and will be discussed later. For a more detailed discussion of IIS security, please see "Implementing a Secure Site with ASP" by Paul Enfield.

IUSR_ComputerName

When IIS is set up on your server, an account named "IUSR_ComputerName" is created. For example, if your IIS machine is named "WebHost", then an account named "IUSR_WebHost" is created. This account is assigned a random password. IIS also sets the "Allow anonymous access" option to "On" by default. If you do nothing else, anonymous users will have access to your Web. This creates a problem with messaging applications that will be discussed later.

Creating Your Own Anonymous User

Another option is that you can create your own user account to access your Web. Reasons to create an account include:

  • Wanting to have a more identifiable name.
  • Creating multiple "anonymous" users on the same IIS machine, where different "anonymous" users use different directories on your Web (IIS 4.x only).

In order to create your own anonymous user, you need to set up several components of Windows NT, Exchange, and Internet Information Server (IIS) correctly. This example creates a new user on the domain using User Manager for Domains, the Microsoft Exchange Administrator, and the Internet Service Manager.

User Manager for Domains

  1. Open the User Manager and from the User menu, choose New User. Set the following properties:
    Username: AnonUser
    Full Name: Anonymous User.
    Description: For anonymous Web access.
    Password: Fill in an appropriate password.
    Confirm Password: Repeat password.
    User Must Change Password at Next Logon: OFF
    User Cannot Change Password ON*
    Password Never Expires: ON*
    Account Disabled: OFF
    Groups—Member of: Domain Users and Domain Guests.
    Profiles: User Profiles or Home Directory settings are not required.
    Hours: No settings are required.
    Logon to: Set as appropriate.
    Account—Account Expires Never.
    Account—Account Type Global Account for regular user accounts in the domain.
    Dialin—Grant dialin permissions to user OFF
    Dialin—Call Back No Call Back.

    *You may set these values to OFF. If you set these values OFF, you need to make sure to keep the password that IIS has in synch with the password that the Windows NT account has.

  2. Click Add. If you have configured your server to automatically create an Exchange account, the Exchange User Properties dialog box appears. If the dialog box does not appear, you need to open the Microsoft Exchange Administrator and create a new mailbox.
  3. Before or after creating the new mailbox, click User Rights from the Policies menu in the User Manager. Click Log on Locally from the drop-down menu on the right. Click Add and add the AnonUser. The user you created now has rights to log on locally to the IIS server.

Microsoft Exchange Administrator

  1. Fill in the following properties on the General tab:
    First Name: Anonymous
    Last Name: User
    Display: Anonymous User
    Alias: AnonUser
    Primary NT Account: DOMAIN\AnonUser
  2. You do not need to set any other properties. Click OK.

Microsoft Internet Service Manager (IIS 4.0)

Select your Web and set the following properties of the Directory Security tab:

NTLM

In IIS, NT Challenge Response refers to NTLM authentication. In NTLM authentication, the IIS machine challenges the client to hash a random value. IIS sends the same random value to the Primary Domain Controller. It then compares the results of the Client and the PDC hash. If the hashes match, the client is authenticated. This is how authentication works on a Windows NT domain.

The problem with this authentication is that it requires the user to have an account on the NT domain. Because most Internet developers want to allow the world to access their Web, "Anonymous" authentication was developed to allow unknown users onto a Web.

Basic

In Basic authentication, IIS challenges the client to provide the DOMAIN\UserID and password. In this case, the password goes over the wire in Base 64. You would want to use Basic authentication when you need the IIS computer to know the user's password. This is necessary in any case where you want IIS to access resources on another Windows NT server.

Opening a user's Exchange account located on a different server is an excellent example of why you would need to use Basic authentication.

IIS decision tree

When a browser tries to access a file, in this case an ASP, IIS determines who has access rights to the file in a certain order. This decision tree will play a large part in how you set up your messaging application.

  • Anonymous Access. First IIS determines whether or not the file is available for anonymous access. If it is, then IIS allows the file to be opened as "Anonymous". In this case, the user will come in under whatever identity has been set up under IIS "Anonymous Access" dialog box. When IIS is installed on the system, the computer's name, prefaced with "IUSR_", is set as the default "Anonymous User". If your computer is named "WebHost", then the default Anonymous User will be "IUSR_WebHost". There are two problems with trying to use this account to interact with Exchange. IUSR_WebHost is not a Windows NT Domain User, and IUSR_WebHost does not have an Exchange account. In order to use IUSR_WebHost to gain access to Exchange, you need to make IUSR_WebHost a Windows NT domain user, and you must give the account an Exchange mailbox. You also need to synch up the passwords that you assign IUSR_WebHost in the User Manager for Domains and in IIS. To do this, follow the procedures outlined above.
  • NTLM. If the file the user is trying to access is not available to anonymous users, then IIS determines whether or not NTLM is allowed. If you have checked the NT Challenge Response box in IIS, then IIS will attempt to use NTLM to validate the user. If that fails, IIS moves on to the Basic authentication method.
  • Basic Authentication. If all other authentication methods have either failed or were not allowed, then IIS will attempt to validate the user with Basic authentication. Under this method, IIS will prompt the browser for logon information. The browser will then produce a dialog box requesting the User ID and password. The user then supplies a DOMAIN\UserID and password. The password is then sent to IIS using base 64. IIS now has the user's password and can validate it with Exchange.

Exchange Security

The Exchange Server is designed to maintain security so that users cannot access mailboxes to which they do not have access rights.

NTLM

To guard against unauthorized access, Exchange uses NTLM. That means that whenever a client tries to access an Exchange mailbox, Exchange challenges the client to hash a random value. Exchange will send the same random value to the PDC to hash. Exchange will then compare the encrypted tokens. If they match, then Exchange will allow the client into the mailbox.

Application Considerations

Now that we've discussed security, it's time to talk about some of the things we need to consider in designing our application. By this, I'm referring as much to network architecture as to the way that you want to write your application.

Password

One of the first questions you need to address is whether or not you want users to send their password from the client's browser to the IIS computer. If your application is going to be used in an intranet solution, then you may decide that it is OK for users to enter their password for transmission across the intranet. On the other hand, if you are designing an application for use on the Internet, I would not recommend designing your application such that users will need to send their password over the Internet to gain access to their mail account.

Sender Identification

You also need to consider whether you want to identify who is sending the mail. If you want the user to access his or her Exchange mailbox, then the user will have to be identified. On the other hand, if you just want mail to generate mail and you do not need to know who it came from, then you do not need to identify your user.

Network Architecture

Your network architecture must reflect what your primary concerns are. Your two choices are to have IIS and Exchange Server on the same computer or to have them on separate computers. There are advantages and disadvantages to both. The way your network needs to be set up is dependent on your answer to the above questions.

IIS and Exchange Colocated

If you require the ability to:

  • Identify who sent the message and
  • You do not want to send the user's password over the Internet,

then you must have IIS and Exchange Server on the same computer. Here's why:

The inescapable facts are that Exchange Server needs an account to send mail from, and that it uses NTLM to authenticate the user. This means that IIS needs to authenticate the user to Exchange. IIS authenticated the user when the user requested access to a Windows NT resource (the ASP). When this happened (assuming that "Allow Anonymous" is not on), IIS sent a random value to the client. The client returned the domain, UserID, and the random value hash. IIS sent the domain, UserID, and random value to a domain controller. The domain controller used that information to hash the random value and sent it back to IIS. IIS then compared the two hashes. If they were the same, then it granted the user access to the resource.

Now that IIS has authenticated the user, it can authenticate the user to Exchange Server only if IIS and Exchange are on the same computer. IIS cannot authenticate the user to an Exchange Server on another computer because IIS does not know the user's password.

Internet

If you are designing a mail system that will be open to the Internet, then security should be a bigger concern. Designing a system that requires users to send their password over the Internet might not be a good idea.

IIS and Exchange Separate

If, on the other hand, you are running in the confines of an intranet where you feel comfortable passing users' passwords over the wire, then you have the option of having IIS and Exchange on separate computers.

It has been my experience that most companies have their IIS and Exchange Servers on different computers. In this configuration, if you want users to access their own Exchange mailbox from an ASP, they will need to enter their password in order for IIS to authenticate them to Exchange Server.

Intranet

If you are designing a mail system to be used exclusively on your intranet, you may decide that sending a user's password over the wire is not a big security concern. In this case you will be able to separate IIS and Exchange. This would allow you to distribute the load over more servers and have a server designed to do one job.

Your Decision Tree

Given the above information, you need to decide how you are going to set up your application and your network. The following two illustrations are flow charts that you can use to help determine how to set up your application. The first flow chart assumes that you have total control over both the network architecture and the application design. Its purpose is to help you determine how to design your network to meet your application requirements.

The second flow chart assumes that you are locked into a network architecture and helps you determine how to set up your Web based on what your network will allow.

Application Requirements

Besides setting up your architecture and configuring your servers, you need to decide how to design your application. This decision should be based upon what you want your application to do.

Simple—Use VBScript

If you are creating a rather simple application that receives recipient, subject, and text from a user and simply sends the mail, this can be accomplished by using a couple of files. I use an HTM file to collect information from the user, then post the information to an ASP file, which sends the message.

You can also use straight ASP code to retrieve information about users from the address book and can even incorporate a filter so you limit the amount of information that the address book returns.

Complex—Consider a Visual Basic DLL

Alternatively, if you plan on designing a complex application that makes intelligent decisions, for example, routing a message to a particular manager depending on what information the user provided, then you may want to write a Visual Basic® DLL for the messaging part of the application. This would be advantageous because you can early bind your objects in Visual Basic, saving memory, and you will be able to reuse the code in other applications.

The Basics

In order to send mail from an ASP you need to create a Session, a Message, and a Recipient. While you do not have to create an Outbox, it is often easier to understand if you explicitly create all the objects that you will use.

Objects

MAPI.Session

You need to create a session object that will perform your mail operations. This is the part of the application that will talk to Exchange Server.

Creating

The following line of code creates your MAPI Session:

Set objSession=CreateObject("MAPI.Session")

Logon

After your session is created, you will need to log onto it. You need to log onto the session either using the UserID of the person who has accessed the ASP, or with the account of the "Anonymous" user that you have defined and created an Exchange account for. Generally speaking, it is easier to create your login line to create a profile "on the fly." This profile is destroyed after the session is destroyed. Since this code is running on the server, it has the added advantage of not needing to store profiles on the server.

In order to create a profile on the fly, you need the UserID and the name of an Exchange Server on the same site as the user's mailbox. This information is concatenated into a string that is passed as the last parameter of the login command.

Fortunately, we can get this information without user intervention. You only need to have the name of an Exchange Server on the same site where your user's mailbox is located. Since you are writing an application for a particular Web to run on an Exchange mail system, I'll assume that you know the name of at least one Exchange server on the network.

StrServer="AnExchangeServer"

The mailbox will be the same as the UserID. If you are using an anonymous account, hardcode the mailbox name. The following code will retrieve the DOMAIN\UserID from ServerVariables and then manipulate the string to return just the UserID.

strLogonID = Request.ServerVariables("Logon_User")
strMailbox = Right(strLogonID, Len(strLogonID) - _ 
             InStr(strLogonID, "\"))

Then put all this information together into the Logon statement:

strProfileInfo = strServer & vblf & strMailbox
objSession.Logon "", "", False, True, 0, True, _
                 strProfileInfo

For more information on each of the logon parameters, please refer to the MSDN Library or to the CDO Help file.

Outbox

While it is not necessary to create the Outbox object in order to create a message, it is more clear.

Set objOutbox=objSession.Outbox

Message

Add the message to the Outbox:

Set objMessage=ObjOutbox.Messages.Add

Recipients

Add a recipient to the message:

Set objRecipient = objMessage.Recipients.Add
objRecipient.Name = strRecipient
objRecipient.Resolve

Methods

Send

The only method required to send a mail message is the Send method:

ObjMessage.Send

Web application

You need to keep control of your objects or your server could crash. One problem is that if a user starts an instance of CDO.DLL on the server, then exits the application by destroying the browser, the session object could remain in memory, causing problems for subsequent users. This could even crash your server, necessitating a reboot. Because of this, creating a Web application with a global.asa file is recommended.

Global ASA

Global.asa contains scripts that affect the Application object and Session object. For example, Global.asa scripts make application- and session-scope variables available at startup. Global.asa should be present at the application root level for every ASP application.

Procedures declared in the Global.asa file can only be called from one or more of the scripts associated with the Application_OnStart, Application_OnEnd, Session_OnStart, and Session_OnEnd events. They are not available to the ASP pages in the ASP-based application.

Application_OnStart. This function runs when a user accesses a Web application that is not currently running. It is distinguished from Session_OnStart because it runs only the first time that an application is accessed. Use the Global.asa to create application-level variables and objects.

Application_OnEnd. This function runs when the last person exits an application. Use this function to clean up any application-level objects that you created in Application_OnStart.

Session_OnStart. This function runs when a new client accesses a Web. This function will run every time that a client accesses a Web. This is as opposed to the Application_OnStart, which runs when a client accesses an application that is not running. Use this function to create session-level variables and objects.

Session_OnEnd. This function runs when a client leaves a Web. It is very useful for catching when a user destroys their browser. Use this function to destroy any session-level objects you created in Session_OnStart.

Include files

An include file has an extension of “.inc” and is just a text file that contains script. You add the script to an ASP by using an “Include” line in the ASP.

<!--#include file="AnonLogon.inc"-->

Include files are useful because you can have ASP files that perform general tasks (like logging on to and logging off a MAPI.Session) and then include files that do more specific things, like send mail from a particular location or format.

Examples

You can download two sample files from the top of this article: AuthMail and AnonMail. Each .exe file contains the files that comprise a Web application.

AuthMail

This sample shows how to create an authenticated Active Messaging session, which will allow the user to access his or her own Exchange mailbox to send mail. Unless you have IIS and Exchange Server installed on the same computer, you will need to use "Basic" authentication to the Web. This is necessary so IIS can authenticate the user to Exchange Server.

File Purpose
AuthLogon.asp This .asp file demonstrates using the functions in AuthLogon.inc. It causes an Active Messaging session to be created (or finds an existing Active Messaging session, if one has already been created by this user) and reads some properties from the session. The file then sends a message to your mailbox (it assumes that your UserID is your mailbox).
AuthLogon.inc This include file contains all of the VBScript code necessary to log on to an Exchange Server. It uses your UserID as your mailbox by pulling your UserID out of your LOGON_USER identification.
SendMail.inc This .inc file contains VBScript and HTML to retrieve recipient, subject, and message from the user, and sends the mail.
AuthLogoff.asp This .asp files causes the Active Server session to be abandoned. As a side effect, the Active Messaging session will also be destroyed.
Global.asa Active Server startup and shutdown functions.

To install:

On the IIS computer:

  1. Install IIS 4.0 from the NT 4.0 Option Pack.
  2. If you do not have Exchange Server installed on the same computer, install a mail client (Outlook® 98) on the IIS computer. This will install the required CDO and support files.
  3. Open UserManager (%SystemRoot%\system32\usrmgr.exe MachineName).
  4. Under the "Policy" menu, select "User Rights..."
  5. Select "Log on Locally" in the "Right:" drop-down box.
  6. Add any user(s) or group(s) that you want to allow access to this Web.
  7. Copy the contents of this zip file into the same directory on your IIS computer (for example, "c:\Webs\AuthMail").
  8. Open the Microsoft Management Console.
  9. Right click on the on the "Default Web Site" and select to create a "New...Virtual Directory".
  10. Fill in the name of the new Web (for example, AuthMail) and click "Next".
  11. Point to the directory containing the files from this .exe file and select "Next".
  12. Select to allow "Read", "Script", and "Execute" Access and click "Finish".
  13. Right click on the new Web and select "Properties".
  14. On the "Virtual Directory" tab, you should have an application created. If the "Create" button in the "Application Setting" frame is available, click it to create your Web. This will change the virtual directory into a Web application. This is necessary for the proper handling of the Global.asa in this example. You do not need to run this application in its own memory space.
    Note   If you have a "Remove" button, then you already have a Web application.
  15. Select the "Directory Security" tab and click on the "Edit" button under "Anonymous Access and Authentication Control".
  16. Deselect "Allow Anonymous" and "NT Challenge Response". Select "Basic Authentication". This will force the user to supply logon credentials to IIS, which will use those credentials to authenticate the user to Exchange Server.
  17. Click "OK" or "Apply" until you're out of UserManager.

To run:

  1. From IE 4.0, access the Web (http://MyWebServer/AuthMail).
  2. You will be pulled to AuthMail.asp.
  3. Enter the Recipient, Subject, and Text in the appropriate text box.
  4. Click the "Submit" button.

AnonMail

This sample shows how to create an anonymous Active Messaging session and send mail from it. In order for this application to work you must configure the anonymous user on your network by following these procedures:

File Purpose
AnonLogon.asp This .asp file demonstrates using the functions in AnonLogon.inc. It causes an Active Messaging session to be created (or finds an existing Active Messaging session if one has already been created by this user) and reads some properties from the session. The file then calls SendMail.inc, which has a function that both collects data from the user and sends the mail to the recipient.
AnonLogon.inc This include file contains all of the VBScript code necessary to log on to an Exchange Server account. The main difference between this file and AuthLogon.inc (an example of an authenticated logon) is that it does not check your authentication, and it requires you to code in the mailbox you want to send mail from.
SendMail.inc This .inc file contains VBScript and HTML to retrieve recipient, subject, and message from the user, and sends the mail.
AnonLogoff.asp This .asp files causes the Active Server session to be abandoned. As a side effect, the Active Messaging session will also be destroyed.
Global.asa Active Server startup and shutdown functions.

On the NT Domain:

  1. Create a User account and give it a password.
  2. Create an Exchange mailbox for that User account.

On the IIS computer:

  1. Install IIS 4.0 from the NT 4.0 Option Pack.
  2. Install a mail client (Outlook 98) in the IIS computer. This will install the required CDO and support files.
  3. Open UserManager (%SystemRoot%\system32\usrmgr.exe MachineName).
  4. Under the "Policy" menu, select "User Rights..."
  5. Select "Log on Locally" in the "Right:" drop-down box.
  6. Add the User you created on the NT Domain to this right.
  7. Copy the contents of this .exe file into the same directory on your IIS computer (for example, "c:\Webs\AnonMail").
  8. Open the Microsoft Management Console.
  9. Right click on the on the "Default Web Site" and select to create a "New...Virtual Directory".
  10. Fill in the name of the new Web (for example, AnonMail) and click "Next".
  11. Point to the directory containing the files from this .exe file and select "Next".
  12. Select to allow "Read", "Script", and "Execute" Access and click "Finish".
  13. Right click on the new Web and select "Properties".
  14. On the "Virtual Directory" tab you should have an application created. If the "Create" button in the "Application Setting" frame is available, click it to create your Web. This will change the virtual directory into a Web application. This is necessary for the proper handling of the Global.asa in this example. You do not need to run this application in its own memory space.
    Note   If you have a "Remove" button, then you already have a Web application.
  15. Select the "Directory Security" tab and click on the "Edit" button under "Anonymous Access and Authentication Control".
  16. Select "Allow Anonymous" and then click the "Edit" button near "Allow Anonymous".
  17. Fill in the DOMAIN\UserID you created on the NT Domain.
  18. Uncheck the "Enable Automatic Password Synchronization" checkbox. This feature is for local machine accounts only.
  19. Fill in the Password you gave the User you created on the NT Domain.
  20. Click "OK" or "Apply" until you're out of UserManager.

Writing Your ASP

Tips

I highly recommend the article by Roger Jack titled "Top Ten ASP Tips," published in the January 1998 issue of Microsoft Internet Developer (MIND).

Notepad

You can write your ASP and HTM in Notepad if you like. Save the files with the appropriate extension and save them to your Web.

Visual InterDev

I prefer to write my Web applications in Microsoft Visual InterDev™ for two reasons. I like the way it color codes. I can easily find a missing ">", and I can easily pick my VBScript code out from the rest of the code on the screen. The second reason is that I like the way I can use Visual InterDev to manage my Web, and that I can work on the same Web from different machines, and not have to keep track of what the latest file is. If I connect to my Web Visual InterDev and start to use a file, Visual InterDev will inform me that there is a newer version of the file available, and ask which one I want to use.

Troubleshooting and Debugging

Unfortunately, at this time, debugging an application is not that easy. The debugging tools are not as robust as in Visual Basic or Visual C++®. This is one reason that if I have a complicated application, I’ll write it in Visual Basic, and then create a DLL for use by my ASP.

Response.Write

The method I employ most is to use Response.Write to find out where my application is and what it thinks is going on. The Response.Write line looks something like:

    Response.Write(“Print out this string <br>”)

You can add variables to the statement as such:

    Response.Write(“objSession.CurrentUser = “ & _  
        objSession.CurrentUser & “<br>”)

For brevity I use the following subroutine loaded in the head of my ASP files:

   <%
    Sub Write(strtext)
        Response.Write(strText & "<br>")
    End Sub
%>

Then I call it from within the script as such:

    Write("ServerName = " & strServer)

ServerVariables

Another thing I do is to load the following routine in the beginning of the ASP.

    <TABLE BORDER=1 CELLPADDING=5 WIDTH=80%>
    <TR><TD><B>Server Variable</B></TD><TD><B>Value</B></TD></TR>
    <% 
        For Each name In Request.ServerVariables %> 
          <TR><TD><%=name%></TD>
          <TD><%= Request.ServerVariables(name)%></TD>
          </TR>
        <% Next %> 
    </TABLE>

This routine prints out all of my server variables in a table. This is useful if I start to run into security problems. I can compare what the Web session variables are with what the messaging session variables are.

Common MAPI Errors

This section describes some common errors that are seen when you use CDO from an ASP. It provides the error code, the reason(s) for the error, and a brief description of how to resolve the problem. When available, KB articles are referenced. To check for more KB articles, please see http://support.microsoft.com/support/messagingsdk/faq/.

MAPI_E_FAILONEPROVIDER

Error Message:

Collaboration Data Objects error '00000505'

You do not have permission to log on. [Microsoft Exchange Server Information Store - [MAPI_E_FAILONEPROVIDER(8004011D)]]

Don’t have permissions

You are trying to access a mailbox that the ASP does not have proper permission for.

Check to make sure the ASP is being authenticated into the account you want. Insert this line into your VBScript to find out what account the ASP is running in:

Response.Write("You are logged on as " & Request.ServerVariables("LOGON_USER") & "<br>")

If you are logged in under the anonymous account, you will receive a blank string back.

Incompatible browser

You are using "NT Challenge Response" as your authentication type, and Netscape Navigator for your browser.

Netscape Navigator does not support "NT Challenge Response" as an authentication option. In order to log onto a user's Exchange account, the IIS authentication needs to be set up as "Basic (Clear Text)".

Public folders

You are trying to gain programmatic access to Public Folders by assigning the folders collection to an object.

You can not gain programmatic access to a public folder from an ASP by stepping through the tree. You need to use GetFolder, which in turn requires you to know what the RootID of the Public Folder. You can use a MAPI property tag (for example, bstrPublicRootID = objInfoStore.Fields.Item( &H66310102 ).Value) to get the root ID of the Public Folders.

MAPI_E_LOGON_FAILED

Resource does not exist

You are trying to access a mailbox that does not exist.

Check the name of the mailbox to make sure it exists.

Note   You can successfully run the Logon line using a resource that does not exist. When you attempt to use a server object (for example, an Outbox or an Inbox) for the first time you will get this error.

Password synchronization

This happens when you are attempting to access an Exchange mailbox that has been set up to allow Anonymous access to Exchange. This is most frequently done to allow users to send mail from a Web application using Microsoft Exchange where you do not need to or are unable to authenticate the user with Windows NT Challenge\Response Authentication (also referred to as NTLM) or Basic Authentication.

Internet Information Server (IIS) version 4.0 has an additional feature that allows for password synchronization between IIS 4.0 and the computer user accounts. Password synchronization should only be used with anonymous user accounts defined on the local computer, not with anonymous accounts remote computers. This feature will not work to authenticate an anonymous user to a remote Exchange server.

Log on locally

You must make sure that the account you are using to log onto Exchange has rights to log on locally. You do this through the User Manager. Select “Policies… User Rights”. Use the drop down to select “Log on Locally” and make sure that the account you want to use either has explicit rights, or is part of a group that has rights to log on locally. If the account does not have rights, add it using the “Add” button.

MAPI_E_NOT_INITIALIZED

Session

Cause:

Trying to access methods and properties without properly logging onto a session variable.

Make sure you have a valid logon before trying to access information store data.

See the KB article Q193451 PRB: "Error 8002009 - MAPI_E_NOT_INITIALIZED 80040605" w/ CDO for more information.

MAPI_E_NOT_FOUND

Resource does not exist

You are trying to use a resource that does not exist. This usually happens when you try to use a server or log onto a mailbox that does not exist. The most common cause of this is copying and pasting sample code without modifying the server and mailbox variables. Check your sample code for variables that are used in the Session Logon line. Most ASP sample code contains a variable called "strProfileInfo". This is a combination of the server name, a line feed, and the mailbox name. Look for the variables that define the server and mailbox, and make sure that the resources are on your network.

Recipient does not exist

Make sure that the recipient is as specified. If you pass an invalid recipient to CDO in an ASP the only way to resolve the problem is to reenter the recipient. You can not call up the Address Book on the client.

Profile not on server

You need to use the ProfileInfo parameter on the Logon call instead of a specific profile. This allows you to create a profile "on the fly" for the user of the ASP.

The reason for this is that the user will not normally have profiles on the server machine, and the profiles are probably not going to be loaded into HKEY_CURRENT_USER in order to be found by CDO.

References

Paul Enfield, "Implementing a Secure Site with ASP."

Scott Stabbert, "Authentication and Security for Internet Developers."

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