Maximum outgoing message size may be set too low
Topic Last Modified: 2006-12-04
The Microsoft® Exchange Server Analyzer Tool queries the Active Directory® directory service to determine the value for the global settings submissionContLength attribute located at:
CN=Configuration, CN=Services, CN=Microsoft Exchange, CN=OrganizationName, CN=Global Settings, CN=Message Delivery
If the Exchange Server Analyzer finds the value for the submissionContLength attribute to be less than 1024 but greater than 0, a warning is displayed.
This warning indicates that a maximum outgoing message size limit has been set to less than 1 megabyte (MB). Based on network bandwidth and user requirements in your organization, you may want to increase the message size to allow for larger messages. In Exchange 2000 Server and Exchange Server 2007, there is no default message size limit. In Exchange Server 2003, the default size limit for sending and receiving messages is 10,240 KB. This default size limit applies to new installations and to upgrades from Exchange 2000 Server in which no message size limit was set.
You can conserve system resources by setting message size limits that prevent users from sending and receiving large e-mail messages. This will help limit network traffic, save disk space, and improve overall network performance. For Exchange 2000 Server and Exchange Server 2003, you can use the Defaults tab in Message Delivery Properties of your Global Settings to specify message delivery restrictions for incoming and outgoing messages. To set the maximum individual message size, select Maximum (KB), and then in the text box, type a maximum size, in kilobytes (KB). If you do not want to limit the size of messages, select No limit. Senders in your organization receive a non-delivery report (NDR) if they try to send a message to a user who goes beyond the specified size limit. Depending on the NDR settings that you configure in Internet Message Formats, external senders may or may not receive an NDR.
For Exchange Server 2007, you can use the Exchange Management Shell to set the TransportConfig MaxSendSize parameter for your Exchange organization.
It is recommended that you set the maximum message size limit to no more than 30 MB. However, if you need a higher message size limit for messages with large attachments to be sent through your Exchange organization, you may want to increase the maximum outgoing message size limit to more than 30 MB. Increasing the message size limit over 30 MB can slow down your network performance and even cause your system to be more vulnerable to security attacks.
In Exchange System Manager, expand Global Settings, right-click Message Delivery, and then click Properties.
In the Message Delivery Properties dialog box, on the Defaults tab, select the Sending message size limit option and type the size limit you want.
In Exchange Management Shell, run the following command where <size> is entered as the default of "unlimited" or the size in B (Bytes), KB (Kilobytes), or MB (Megabytes) in a range of 0 to 2147483647 bytes:
Set-TransportConfig -MaxSendSize <size>
For example, to set the maximum message size that can be sent by users in the Exchange Organization to 10 Megabytes you would enter:
Set-TransportConfig -MaxSendSize 10MB
To set the maximum message size that can be sent by users in the Exchange Organization to the default value of unlimited you would enter:
Set-TransportConfig -MaxSendSize unlimited
For more details about setting message size limits for Exchange 2000 Server and Exchange Server 2003, see the Microsoft Knowledge Base article 322679, "Set Size Limits for Messages" (http://go.microsoft.com/fwlink/?LinkId=3052&kbid=322679).
For more information about the TransportConfig cmdlet for Exchange Server 2007, see "Set-TransportConfig" in the Exchange Server 2007 Technical Reference (http://go.microsoft.com/fwlink/?LinkID=79237).
For more information about Internet Message Formats, see the topic "Configuring SMTP Policies to Control Outbound Mail Formatting and Automatic Responses" in the Exchange Server 2003 Administration Guide (http://go.microsoft.com/fwlink/?LinkId=47617).