How to Set Outbound Message Limits on Your SMTP Virtual Server

On your SMTP virtual server that handles outbound mail delivery, you can configure connection limits and time-out settings that the server uses with remote servers. Configure these limits to ensure that your server does not get overloaded.

Before You Begin

Before you perform the procedure in this topic, read Connecting Exchange to the Internet.

The following permissions are required to perform this procedure:

• Member of the local administrators group and a member of a group that has had the Exchange Administrators role applied at the administrative group level

Procedure

To set outbound message limits on your SMTP virtual server

1. Click Start, point to Programs, point to Microsoft Exchange, and then click System Manager.

2. In the console tree, expand Servers, expand <Server Name>, expand Protocols, and then expand SMTP.

3. Right-click <Your Outgoing SMTP Virtual Server>, and then click Properties.

4. Click the Delivery tab.

5. Under Outbound,you can modify the time in minutes for first, second, third, and subsequent retry attempts by entering the appropriate values for your organization. These outbound settings control message delivery for mail that is sent outside of the organization.

   Outbound settings on the Delivery tab

   

   Note

   Setting a retry interval to too low of a value may degrade performance, particularly when your Internet connection or the specified smart host is unavailable.

6. Under Local, set Delay notification and Expiration timeout for local message delivery by typing the values in the corresponding boxes, and then selecting the time in Minutes, Hours, or Days. It is recommended that you use the default settings. These local settings apply to mail that is sent to the local mailbox store or in Microsoft Exchange MTA.

   Note

   Systems on the Internet may have different values for delay notification and expiration timeout. The values entered here refer to messages that are queued on this server.

7. Click Outbound connections to configure connection limits and timeout values that the server uses with remote servers. The Outbound Connections dialog box appears.

   The Outbound Connections dialog box

   

8. Depending on your hardware, you can select the Limit number of connections to check box to limit connections to other servers and to reduce traffic. You can also select the Limit number of connections per domain to check box. After you select the check boxes, enter the appropriate values for your organization.

9. Depending on your bandwidth and connection quality, you can change the Time-out (minutes) value.

   Note

   Reducing the number of outbound connections and increasing the time-out period may cause all your outbound connections to wait for responses from remote servers. With such settings, e-mail messages remain in the queue for longer periods of time (potentially causing a delay in message delivery), but network traffic is kept to a minimum.