When I look at the Mailbox Logon view in Exchange System Manager (ESM), I notice that our Outlook clients have multiple connections open. Why does this happen?
This behavior is by design. Outlook can open multiple connections to parallelize its data communications with the Exchange server. The actual number of connections will vary according to the version of Outlook that you're using and the mode in which you're using it. For Microsoft Office Outlook 2003 in Cached Exchange Mode, you'll see four connections for the mailbox, plus additional connections for public folders (including referrals to other public folder servers) and one or more connections to the directory server.