Exchange 2007 - Administratively set mailbox send and receive size limits

These commands can be used in the Exchange Management Shell to set the MaxSendSize and MaxReceiveSize for all mailboxes at once.  If you use a number like 20480, that will set it as KB.  Or you can use MB at the end to shorten it.

get-mailbox | set-mailbox -MaxSendSize 20MB

get-mailbox | set-mailbox -MaxReceiveSize 20MB