C

CA

See certificate authority (CA).

certificate

Binds together the public and private keys that are used for the secure communication and exchange of data, typically over the Internet. Certificates are digitally signed to ensure their validity.

certificate revocation list (CRL)

A document that is maintained by the certificate authority (CA), which lists all certificates that have been revoked. It is used to keep revoked certificates from being misrepresented as valid.

certificate trust list (CTL)

A list published by the certificate authority (CA) that contains a list of certificates that are trusted for a designated purpose such as digitally signing e-mail.

certificate authority (CA)

An issuer of digital certificates that authorizes and vouches for the validity of the certificates it issues and other CAs that it is associated with.

checkpoint file

A file that indicates the location of the last information successfully written from the transaction logs to the database. In a data recovery scenario, the checkpoint file indicates where the recovery or replaying of data should begin.

circular logging

When a log file fills up, it is overwritten with new data rather than having a new log file created. This conserves disk space but can result in data loss in a disaster recovery scenario, as you would be required to restore back to the last full backup.

cluster group

A collection of cluster resources that is used to define the settings that make up a virtual server on a cluster. When a failover occurs on a node of the cluster, it is the cluster group that fails over to another node.

cluster resource

A cluster resource is an individual component of a cluster virtual server, such as an Internet Protocol (IP) address, a network name, or a physical disk. Cluster resources are collected into groups. When a resource fails, it restarts according to a configurable policy. If a resource exceeds its restart threshold, it can force a failover of the entire group it belongs to.

clustering

The process of combining the resources of multiple physical servers to appear to network clients as a single server. Clusters are used to increase fault tolerance and performance.

Configuration Naming Partition

Stores information about the physical structure of the Microsoft Exchange organization, such as routing groups and connectors.

connection agreement

Used by Active Directory Connector to control replication between Active Directory and the Exchange Server 5.5 directory. Connection agreements can be used to replicate from Exchange Server 5.5 to Active Directory, or vice versa, or in both directions.

contact

A mail-enabled object on a Microsoft Exchange server that links to an external e-mail address. Contacts do not have mailboxes on the Exchange server and serve to provide a convenient means of accessing frequently used external e-mail addresses.

container

An object in Active Directory that is capable of holding other objects. An example of a container is the Users folder in Active Directory Users And Computers.

convergence

The method used by network load balanced clusters to mark a server node as non-responsive and to remove it from the cluster. Convergence begins when a server does not respond to five consecutive heartbeat packets.

CRL

See certificate revocation list (CRL).

CTL

See certificate trust list (CTL).