Hi All, we got two sites with single domain, one site is running Exchange 2003 and other side is running Exchange 2007. I try to enable the Full Permission for a user to a mailbox of 2003. I did , in the Exchange 2007 Management console, right click the mailbox of 2003, clicked the option - Manage Full Permission. I found "Everyone" group in the list. Then I checked all the Exchange 2003 mailboxes in Exchange 2007 management console, EVERYONE group is there but not for Exchange 2007 mailboxes. Can anybody please explain how everyone group can be in the list?

Awesome explanation, Thanks Simon.