The glossary below contains many of the terms you will find in common use throughout the Symantec Security Response website. Please refer to this list to find definitions of terms and answers to other Internet security-related questions.


A program that protects the resources of one network from users from other networks. Typically, an enterprise with an intranet that allows its workers access to the wider Internet will want a firewall to prevent outsiders from accessing its own private data resources.

Hardware, software, or a combination of both that is used to prevent unauthorized Internet users from accessing a private network. All information entering or leaving a network must pass through a firewall, which examines the information packets and blocks those that do not meet security criteria. The Symantec Protection Agent component of Symantec Sygate Enterprise Protection Allows, Blocks, or Asks whether incoming traffic is allowed to access an organization’s network or resources. By using firewall rules, an Agent can systematically allow, block, and ask questions of traffic from specific IP addresses and ports. See also firewall rule, Symantec Protection Agent.