Messaging Records Management (MRM) can be used to define polices for retention on specific folders. You can also target an MRM policy to a specific group. There is a 10 minute video that explains MRM on the Exchange Team Blog:
Essentially if you do not have any user mailboxes stores or public folder stores on an Exchange server that is operating as a front end server, then you can safely enable circular logging. This will reduce the disk space requirements for the front end server.
Officially Microsoft does not support the storage of PST files on file shares whether they are on a LAN or WAN. They have a knowledge base article specifically regarding this http://support.microsoft.com/kb/297019 but there is also a good commentary on the subject on the Microsoft Enterprise Platforms Windows Server Performance Team blog Network Stored PST files … don’t do it!
Erik Ashby, Edward Wu and Jenna Lyday give a live-meeting Webcast demonstrating the new Microsoft Transporter Suite for Lotus Domino. They show how the suite can be used for migrating accounts, mailboxes and applications from Domino.
Resources for Interoperability and Migration from Lotus Domino
Microsoft has a tool called the “Microsoft Transporter for Lotus Domino Availability” this tool claims to offer interoperability and migration from Lotus Domino to Active Directory, Exchange Server 2007, and Windows SharePoint Services 3.0.
http://www.microsoft.com/technet/interopmigration/collaboration/default.mspx
PFMIGRATE allows you to move a bunch of Public Folders from an Exchange Server to an Exchange 2003 Server from the command line.
PFMIGRATE.WSF is a Script, which is located on the Exchange 2003 CD and the Exchange 2003 SP1 under SUPPORT\EXDEPLOY.
When using Outlook Web Access (OWA), users are prompted to login after clicking on links.
If you are prompted for credentials when you click a hyperlink to an external Web site, follow these steps:
Exchange 2007 introduces a new Exchange term: “Server Role”. Server role is a logical concept used to organize Exchange 2007 services and features across one or more servers. While Exchange 2003 provided primitive server roles called BackEnd server and FrontEnd server, Exchange 2007 has more granular divisions.
This applies to Exchange Server 2003. It is possible that the behaviors of recipient policies of Exchange 5.5 and Exchange 2000 are similar, if not exactly the same as described here.
On a new installation of Exchange there is a Default Recipient Policy created that contains the email addresses specified during setup through the Internet Mail Wizard. This policy has a priority of lowest and a filter of all mailboxes.