F

failover or failback

The process of moving a resource from one server in a cluster to another. Failover happens when a problem occurs on the active server and services must be transferred to the passive server. Failback is the process of restoring resources to the active server after they have been temporarily relocated on a passive server.

filter rules

LDAP rules created using recipient policies. Filter rules allow you to specify what kind of e-mail address is generated for each recipient object.

firewall

A system designed to prevent unauthorized access to or from a private network. A firewall can be made up of hardware, software, or a combination of both. Firewalls can work by blocking certain types of packets or certain applications.

forest

A collection of domains and domain trees. The implicit name of the forest is the name of the first domain installed. All domain controllers within a forest share the same configuration and schema naming partitions. To join an existing forest, you will use the Dcpromo utility. The first domain within the forest cannot be removed.

front end/back end

An Exchange configuration in which clients access a bank of protocol servers (the front end) for collaboration information, and these in turn communicate with the data stores on separate servers (the back end) to retrieve the physical data. A front-end/back-end configuration allows for a scalable single point of contact for all Exchange-related data.

functional level

The mode in which an Active Directory domain or forest is operating. A domain can exist in a number of functional levels, each of which is determined by the versions of Windows Server running in the domain or forest. In Windows 2000 mixed mode (in which Windows NT, 2000, and 2003 servers can run), the domain has limitations (such as 40,000 objects) imposed by the Windows NT 4 domain model. However, Windows 2000 domain controllers and Windows NT 4 backup domain controllers can coexist within the domain without problems. Switching to Windows 2000 native mode (which allows Windows 2000 and 2003 servers only) allows the directory to scale up to millions of objects. The Windows Server 2003 level provides the full functionality of Windows Server 2003, but requires that all servers run Windows Server 2003.