Allowing large messages in Exchange 2007

Allowing large messages in Exchange 2007

Silly me, I thought it would only take one setting to increase the maximum email/attachment size in Exchange 2007. Unfortunately, there are a number of settings you need to change.

If you are using ForeFront, you have an attachment limit of around 26MB on zip (compressed attachments). See my blog article to fix this issue:
Large attachments being blocked by ForeFront for Exchange Server (2007)

OWA is limited to 30MB. See the Microsoft Technet article:
http://technet.microsoft.com/en-us/library/aa996835.aspx

There are a number of Exchange 2007 message size limits that are set within Exchange to limit message size. For a complete list see the following Microsoft Technet article:
http://technet.microsoft.com/en-us/library/bb124345.aspx

Organizational Limits

The following table shows the organizational limits.

Organizational limits

Source	Parameter	Default value in Exchange 2007 RTM	Default value in Exchange 2007 SP1
Set-TransportConfig	MaxReceiveSize	Unlimited	10 MB
Set-TransportConfig	MaxSendSize	Unlimited	10 MB
Set-TransportConfig	MaxRecipientEnvelopeLimit	Unlimited	5000
Transport rule on a Hub Transport server that applies to all Hub Transport servers in the organization.	AttachmentSizeOver	Not configured	Not configured

Global Limits

The following table shows the global limits.

Global limits

Source	Property	Default value
Active Directory	delivContLength in Active Directory Incoming message size in Exchange System Manager Global Settings in Exchange 2003	10240 KB (10 M
Active Directory	submissionContLength in Active Directory Outgoing message size in Exchange System Manager Global Settings in Exchange 2003	10240 KB (10 M
Active Directory	msExchRecipLimit in Active Directory Maximum number of recipients in Exchange System Manager Global Settings in Exchange 2003	5000

Connector Limits

The following table shows the connector limits.

Connector limits

Source	Parameter	Version	Default value
Set-ForeignConnector	MaxMessageSize	Exchange 2007 RTM and Exchange 2007 SP1	Unlimited
Set-ReceiveConnector	MaxHeaderSize	Exchange 2007 RTM and Exchange 2007 SP1	64 KB
Set-ReceiveConnector	MaxMessageSize	Exchange 2007 RTM and Exchange 2007 SP1	10 MB
Set-ReceiveConnector	MaxRecipientsPerMessage	Exchange 2007 RTM and Exchange 2007 SP1	200
Set-SendConnector	MaxMessageSize	Exchange 2007 RTM and Exchange 2007 SP1	10 MB
Set-AdSiteLink	MaxMessageSize	Exchange 2007 SP1	Unlimited
Set-RoutingGroupConnector	MaxMessageSize	Exchange 2007 SP1	Unlimited

Server Limits

The following table shows the server limits.

Server limits

Source	Parameter	Default value
Transport rule on an Edge Transport server that only applies to the specific server	AttachmentSizeOver	Not configured
Set-TransportServer on a Hub Transport server or Edge Transport server	PickupDirectoryMaxHeaderSize	64 KB
Set-TransportServer on a Hub Transport server or Edge Transport server	PickupDirectoryMaxRecipientsPerMessage	100
Outlook Web Access Web.config file on a Client Access server	maxRequestLength	30000 KB

User Limits

The following table shows the user limits.

User limits

Source	Parameter	Default value
Set-DistributionGroup	MaxReceiveSize MaxSendSize	Unlimited
Set-DynamicDistribution Group	MaxReceiveSize MaxSendSize	Unlimited
Set-Mailbox	MaxReceiveSize MaxSendSize RecipientLimits	Unlimited
Set-MailContact	MaxReceiveSize MaxSendSize MaxRecipientPerMessage	Unlimited
Set-MailPublicFolder	MaxReceiveSize MaxSendSize	Unlimited
Set-MailUser	MaxReceiveSize MaxSendSize RecipientLimits	Unlimited

Internet to Edge Transport Server

Scope	Source	Parameter	Default value in Exchange 2007 RTM	Default value in Exchange 2007 SP1
Connector	Receive connector	MaxRecipientsPerMessage	200	200
Connector	Receive connector	MaxMessageSize	10 MB	10 MB
Connector	Receive connector	MaxHeaderSize	64 KB	64 KB
Server	Transport rule	AttachmentSizeOver	Not configured	Not configured
Edge Transport server Organization	Transport configuration	MaxReceiveSize	Unlimited	10 MB
Edge Transport server Organization	Transport configuration	MaxRecipientEnvelopeLimit	Unlimited	5000
Edge Transport server Organization	Transport configuration	MaxSendSize	Unlimited	10 MB

Anonymous senders are always subject to the message size limits on the Receive connector that accepts messages from the Internet.

The default value of the MaxRecipientsPerMessage setting on the Receive connector is 200 recipients. If the number of recipients is exceeded for an anonymous sender, the message is accepted for the first 200 recipients. Most SMTP messaging servers will detect that a recipient limit is in effect. The SMTP messaging server will continue to resend the message in groups of 200 recipients until the message is delivered to all recipients.

Edge Transport Server to Hub Transport Server

Scope	Source	Parameter	Default value in Exchange 2007 RTM	Default value in Exchange 2007 SP1
Connector on Edge Transport server	Send connector	MaxMessageSize	10 MB	10 MB
Connector on Hub Transport server	Receive connector	MaxRecipientsPerMessage	200	200
Connector on Hub Transport server	Receive connector	MaxMessageSize	10 MB	10 MB
Connector on Hub Transport server	Receive connector	MaxHeaderSize	64 KB	64 KB
Recipient	Distribution group Dynamic distribution group Mailbox Mail contact Mail-enabled public folder Mail user	MaxReceiveSize	Unlimited	Unlimited
All Hub Transport servers in the organization	Transport rule	AttachmentSizeOver	Not configured	Not configured
Organization	Transport configuration	MaxReceiveSize	Unlimited	10 MB
Organization	Transport configuration	MaxRecipientEnvelopeLimit	Unlimited	5000
Organization	Transport configuration	MaxSendSize	Unlimited	10 MB

An X-header that is named X-MS-Exchange-Organization-OriginalSize: is inserted into the message header. Any Hub Transport servers that are involved in the future delivery of the message will use this value for the message size. Conversion encoding and agent processing can increase the size of the message as it flows through the Exchange organization.

Hub Transport Server to Hub Transport Server in the Same Active Directory Forest

Scope	Source	Parameter	Default value in Exchange 2007 RTM	Default value in Exchange 2007 SP1
Sender	Distribution group Dynamic distribution group Mailbox Mail contact Mail-enabled public folder Mail user	MaxSendSize	Unlimited	Unlimited
Recipient	Mail contact	MaxRecipientPerMessage	Unlimited	Unlimited
Recipient	Mailbox Mail user	RecipientLimits	Unlimited	Unlimited
Recipient	Distribution group Dynamic distribution group Mailbox Mail contact Mail-enabled public folder Mail user	MaxReceiveSize	Unlimited	Unlimited
All Hub Transport servers in the organization	Transport rule	AttachmentSizeOver	Not configured	Not configured
Organization	Transport configuration	MaxReceiveSize	Unlimited	10 MB
Organization	Transport configuration	MaxRecipientEnvelopeLimit	Unlimited	5000
Organization	Transport configuration	MaxSendSize	Unlimited	10 MB

In Exchange 2007 SP1, you can set a maximum message size limit on an Active Directory site link or a routing group connector. For more information, see How to Configure Message Size Limits for Internal Routing.

Hub Transport Server to Hub Transport Server in Different Active Directory Forests

Scope	Source	Parameter	Default value in Exchange 2007 RTM	Default value in Exchange 2007 SP1
Sender	Distribution group Dynamic distribution group Mailbox Mail contact Mail-enabled public folder Mail user	MaxSendSize	Unlimited	Unlimited
Connector	Send connector	MaxMessageSize	10 MB	10 MB
Connector	Receive connector	MaxRecipientsPerMessage	200	200
Connector	Receive connector	MaxMessageSize	10 MB	10 MB
Connector	Receive connector	MaxHeaderSize	64 KB	64 KB
Recipient	Mail contact	MaxRecipientPerMessage	Unlimited	Unlimited
Recipient	Mailbox Mail user	RecipientLimits	Unlimited	Unlimited
Recipient	Distribution group Dynamic distribution group Mailbox Mail contact Mail-enabled public folder Mail user	MaxReceiveSize	Unlimited	Unlimited
All Hub Transport servers in the destination organization	Transport rule	AttachmentSizeOver	Not configured	Not configured
Destination Organization	Transport configuration	MaxReceiveSize	Unlimited	10 MB
Destination Organization	Transport configuration	MaxRecipientEnvelopeLimit	Unlimited	5000
Destination Organization	Transport configuration	MaxSendSize	Unlimited	10 MB

If a specific Receive connector is configured in the destination Active Directory forest to accept messages from the source Active Directory forest, that specific Receive connector should have the ExchangeServers permission group and the ExernalAuthoratative authentication method assigned. This permission group contains the Ms-Exch-Bypass-Message-Size-Limit permission that allows messages to flow through the Receive connector without checking the message size. The message is still be subject to organization, transport server, sender, and recipient limits that are defined in the destination Active Directory forest.

For more information, see Configuring Cross-Forest Connectors.

Mailbox Server to Hub Transport Server

Scope	Source	Parameter	Default value in Exchange 2007 RTM	Default value in Exchange 2007 SP1
Sender	Distribution group Dynamic distribution group Mailbox Mail contact Mail-enabled public folder Mail user	MaxSendSize	Unlimited	Unlimited
Recipient	Mail contact	MaxRecipientPerMessage	Unlimited	Unlimited
Recipient	Mailbox Mail user	RecipientLimits	Unlimited	Unlimited
Recipient	Distribution group Dynamic distribution group Mailbox Mail contact Mail-enabled public folder Mail user	MaxReceiveSize	Unlimited	Unlimited
All Hub Transport servers in the organization	Transport rule	AttachmentSizeOver	Not configured	Not configured
Organization	Transport configuration	MaxReceiveSize	Unlimited	10 MB
Organization	Transport configuration	MaxRecipientEnvelopeLimit	Unlimited	5000
Organization	Transport configuration	MaxSendSize	Unlimited	10 MB

Submission by a Foreign Connector

Scope	Source	Parameter	Default value in Exchange 2007 RTM	Default value in Exchange 2007 SP1
Sender	Distribution group Dynamic distribution group Mailbox Mail contact Mail-enabled public folder Mail user	MaxSendSize	Unlimited	Unlimited
All Hub Transport servers in the organization	Transport rule	AttachmentSizeOver	Not configured	Not configured
Connector	Foreign connector	MaxMessageSize	10 MB	10 MB
Organization	Transport configuration	MaxReceiveSize	Unlimited	10 MB
Organization	Transport configuration	MaxRecipientEnvelopeLimit	Unlimited	5000
Organization	Transport configuration	MaxSendSize	Unlimited	10 MB

Submission by the Pickup Directory

Scope	Source	Parameter	Default value in Exchange 2007 RTM	Default value in Exchange 2007 SP1
Server	Transport server	PickupDirectoryMaxHeaderSize	64 KB	64 KB
Server	Transport server	PickupDirectoryMaxRecipientsPerMessage	100	100
Server	Transport rule	AttachmentSizeOver	Not configured	Not configured
Organization	Transport configuration	MaxReceiveSize	Unlimited	10 MB
Organization	Transport configuration	MaxRecipientEnvelopeLimit	Unlimited	5000
Organization	Transport configuration	MaxSendSize	Unlimited	10 MB

Submission by the Replay Directory

Scope	Source	Parameter	Default value in Exchange 2007 RTM	Default value in Exchange 2007 SP1
Server	Transport Rule	AttachmentSizeOver	Not configured	Not configured
Organization	Transport configuration	MaxReceiveSize	Unlimited	10 MB
Organization	Transport configuration	MaxRecipientEnvelopeLimit	Unlimited	5000
Organization	Transport configuration	MaxSendSize	Unlimited	10 MB

Hub Transport Server to Edge Transport Server

Scope	Source	Parameter	Default value in Exchange 2007 RTM and Exchange 2007 SP1
Sender	Distribution group Dynamic distribution group Mailbox Mail contact Mail-enabled public folder Mail user	MaxSendSize	Unlimited
Connector on Hub Transport server	Send connector	MaxMessageSize	10 MB
Connector on Edge Transport server	Receive connector	MaxRecipientsPerMessage	200
Connector on Edge Transport server	Receive connector	MaxMessageSize	10 MB
Connector on Edge Transport server	Receive connector	MaxHeaderSize	64 KB

Edge Transport Server to the Internet

Scope	Source	Parameter	Default value in Exchange 2007 RTM	Default value in Exchange 2007 SP1
Server	Transport Rule	AttachmentSizeOver	Not configured	Not configured
Edge Transport server Organization	Transport configuration	MaxReceiveSize	Unlimited	10 MB
Edge Transport server Organization	Transport configuration	MaxRecipientEnvelopeLimit	Unlimited	5000
Edge Transport server Organization	Transport configuration	MaxSendSize	Unlimited	10 MB
Connector	Send connector	MaxMessageSize	10 MB	10 MB