Message Size Limit in Exchange 2003


How Message size limit works in Exchange 2003

 

  1. All Internet e-mail messages use the global setting for limits on sending and on receiving.
  2. If the SMTP virtual servers have limits it will override the global settings for the internet emails if it is more restrictive
  3. If the connectors have limits it will override the SMTP virtual server and the Global setting limits if it is more restrictive
  4. If the users have mailbox limits it will override the SMTP, connector and Global settings limits if it is more restrictive

The above applies for messages sent to the internet and between routing groups. 

Exception:

The User mailbox limit will override the Global settings even if it is not more restrictive only when sending messages between mailboxes in the same organization (no internet mails) and this only applies if we don’t have limit restrictions on the connectors between the routing groups or restrictions on the receiving SMTP virtual server, if we do have limits on the connectors and the receiving SMTP virtual server then the most restrictive will override.

Note: The size of SMTP messages that are sent between routing groups and to the Internet increase by about 30 to 40 percent if they contain binary attachments or other 8-bit data.

 

Example 1

 In this example, the following size limits have been configured:

- The global setting is set to 5 MB. 

- The Exchange SMTP connector is set to 3 MB.

- The SMTP virtual server is set to 4 MB.

- The user mailbox setting is set to 2 MB.

Because of these settings, users in the Exchange 2003 organization can send and receive messages that are a maximum of 5 MB. Users can send messages through the connector that are a maximum of 3 MB. All mail that passes through the SMTP Virtual Server (sending or receiving) is limited to 4MB. The individual user, whose mailbox setting is 2 MB, is also limited to sending and receiving messages that are a maximum of 2 MB.

 

Example 2 

 In this example, the following size limits have been configured:

- The global setting is set to 2 MB.

- The Exchange 2003 SMTP connector is set to 5 MB.

- The SMTP virtual server is set to 2 MB.

- The user mailbox setting is set to 3 MB.

 

The global setting is 2 MB. Therefore, all the users who are using the default global setting in the Exchange Server 2003 organization are limited to sending and receiving messages that are a maximum of 2 MB.  If an individual user has a mailbox setting of 3 MB, that user overrides the global setting.

Note All Internet e-mail messages use the global setting for limits on sending and on receiving.  The message categorizer evaluates the sender's sending limit and the recipient's receiving limit.  In example 2 earlier, a user with a user mailbox limit of 3 MB could receive messages from another user with a 3-MB sending limit.  Because Internet users use the global setting, they can send only a 2-MB message.

 

For more information about how to configure the message size limit in Exchange 2003 on all different levels please refer to the article below:

 http://support.microsoft.com/default.aspx?scid=kb;EN-US;322679


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