Offline use and remote use are two separate aspects of using Outlook 2007. When you work offline, your computer is not connected to the computer running Exchange Server. This usually means you’re working on a computer that uses a dial-up connection to the server or on a portable computer that you connect to the server through a docking station or a wireless access point on the local area network (LAN). You can be working offline even while your computer is connected to the LAN when the Exchange Server is down for maintenance, or you can deliberately set Outlook 2007 offline.

You can perform most of the same operations offline that you perform when you’re connected to the server. You can create messages, contacts, and other Outlook 2007 items; schedule meetings; and carry out other common Outlook 2007 tasks. The items you create and the changes you make to your folders and their contents, however, are made to the offline store instead of to your Exchange Server mailbox store. When you reconnect to the server, Outlook 2007 synchronizes the offline store with the mailbox store. Any items that arrived in the mailbox while you were working offline are added to your offline store when Outlook 2007 performs the synchronization. This behavior is the same whether you use Cached Exchange Mode and work from a locally cached copy of your mailbox or simply add an offline store (OST) file to your profile—the main difference is in how Outlook 2007 synchronizes the online and offline mailboxes.

In contrast, working remotely generally means working with Outlook 2007 from a location other than the LAN on which the Exchange Server is located. For example, you might dial in to your LAN with a modem, connect to it through the Internet, or even connect through a demand-dial connection between two offices. Whatever your location, you can be working either offline or online when you work remotely. The only consideration is whether you are connected to the server. If you are not connected to the server, you are working offline and remotely. If you are connected to the server, you are simply working remotely.

With the Outlook 2007 remote mail features, you can read message headers without downloading the message itself. Remote mail is useful when you receive a very large message in your mailbox and don’t want to download it, when your mailbox contains a corrupted message that is preventing you from downloading other messages, or when your mailbox contains a message infected by a worm or virus. You can connect with remote mail, delete the message without reading or downloading it, and continue processing the other messages normally. This capability is also generically useful in low-bandwidth situations to give you greater control over which messages you choose to download.