Setting Message Size Limits in Exchange 2010

The organizational send and receive size limits apply to all Exchange servers in the Organization. The default is 10MB.

In Exchange 2007 SP1 and later, you can also set the organizational message size limits using the EMC by going to Organization Configuration | Hub Transport | Global Settings tab | Transport Settings | properties | General tab.

Unlike Exchange SMTP Virtual Servers in Exchange Server 2003/2000, Exchange 2007′s Receive Connectors are only used to receive messages. The maximum message size limit can be different on different Receive Connectors on a Hub Transport or Edge Transport server. For example, a Receive Connector for inbound Internet mail may have lower message size limits, but you may want to allow larger messages on Receive Connector for authenticated senders or partners.

To modify the maximum message size on a Receive Connector using the Exchange console, select Server Configuration | Hub Transport | select a Hub Transport server | Receive Connectors -> select a connector | Properties | General tab.