A newly created recipient may not receive e-mail messages for up to eight hours when you use an Exchange 2007 Edge Transport server in a Microsoft Solution for Hosted Messaging and Collaboration version 4.0 environment

In a Microsoft Exchange Server 2007 environment in which you use Microsoft Solution for Hosted Messaging and Collaboration version 4.0, you experience the following symptoms:

• After a new recipient is created, you experience a delay of up to eight hours before that recipient can receive e-mail messages.
• POP3 clients or IMAP clients cannot relay messages through the Exchange 2007 Edge Transport server.

You experience this issue if an Exchange 2007 server that is configured to use the Edge Transport role is used to perform recipient filtering and to receive SMTP e-mail messages.

This issue occurs because of the following behavior:

• Recipient information must be replicated to the ADAM database on the Edge Transport server. By default, this replication occurs every four hours.
• The Edge Transport server must update its cache. By default, the action occurs every four hours.

Therefore, you may experience a delay of up to eight hours before a newly created recipient can receive e-mail messages. If you do not perform recipient filtering in a new hosted domain, you may still experience a delay of up to four hours before newly created recipients may receive e-mail messages.

Additionally, because an Edge Transport server cannot validate the password that a POP3 client or an IMAP client provides, the Edge Transport server does not support authenticated relaying from these kinds of clients.

Note To handle sending messages by using POP3 or IMAP, Exchange 2007 must validate the user before Exchange 2007 lets the user relay messages. Although you can configure an authenticated relay functionality in Exchange 2007, the password for the user accounts for the POP3 clients or the IMAP clients does not exist on servers that are running the Edge Transport role. Therefore, the users cannot use the account to authenticate.

To work around this behavior, use one of the following methods, as appropriate for your situation.

Method 1: Manually start the synchronization process on the Edge Transport server

To help reduce the delay that occurs between the time that you create a new recipient and the time that the new recipient can receive e-mail messages, you can manually start the synchronization process. To do this, create a cmdlet to start the synchronization task. If you want the synchronization to occur more frequently than every four hours, you can schedule a task that runs the cmdlet.

Note You must not schedule this task to run more frequently than the time that is required to perform a full synchronization operation. We recommend that you do not perform synchronization more frequently than every hour. In a large environment, you may want to perform synchronization less frequently than every hour.

Additionally, you can turn off the recipient cache to help reduce the time that is required for a newly created recipient to receive e-mail messages. However, you may experience a decrease in performance in the Exchange Server environment if you turn off the recipient cache.

Note There is no workaround on an Edge Transport server to let POP3 clients or IMAP clients relay messages.

Method 2: Use a Hub Transport server instead of an Edge Transport server

An Exchange 2007 server that is running the Hub Transport role is not affected by the delays that this article describes. This behavior occurs because a Hub Transport server interacts directly with the Active Directory directory service. Therefore, if you use a Hub Transport server instead of an Edge Transport server, newly created recipients and newly created domains may receive e-mail messages immediately. Additionally, with a Hub Transport server, POP3 clients and IMAP clients can relay messages successfully. However, in a hosting environment, you must carefully consider the security issues that are associated with using a Hub Transport server instead of an Edge Transport server. Additionally, you may experience performance issues if you replace the Edge Transport server with a Hub Transport server.

Therefore, we recommend that you carefully plan and test this kind of deployment before you implement it in a hosting environment.

For more information about Microsoft Solution for Hosted Messaging and Collaboration version 4.0, visit the following Microsoft Web site:To obtain the Microsoft Solution for Hosted Messaging and Collaboration version 4.0 Help file, visit the following Microsoft Web site: