Internet Security and Acceleration Server

What Does Internet Security and Acceleration Server Mean?

An Internet security and acceleration server (ISA server) is a server that provides organizational firewall and Web cache solutions for Windows along with secure, fast and manageable Internet connectivity.


ISA helps to implement an organization’s business security policy through its administrative tools, which help to regulate usage based on user group, application, destination, schedule and content criteria. Its extensible platform offers hardware redundancy and load balancing and enables efficient use of network resources through its sophisticated caching mechanisms.

Techopedia Explains Internet Security and Acceleration Server

ISA server is a member of the .NET enterprise server. It comes in both a standard and enterprise edition. While the standard edition can be used as a stand-alone server (supporting up to four processors) for organizations with lesser access to the Internet, the enterprise edition is used for large-scale deployment due to its additional functionalities.

ISA server uses the following technologies for its services:

  • Microsoft Firewall service to screen all packet-level, circuit-level and application-level traffic
  • A Web proxy to store and serve regularly accessed Web content to reduce network traffic and provide faster access to frequently accessed Web pages
  • Secure network address translation for providing address transparency to networked clients
  • RAM caching and Cache Array Routing Protocol for advanced caching
  • Dynamic Internet Protocol packet filtering to open ports only when needed, thus reducing the risk of external attack
  • Virtual private networking for encapsulating private data over a public network
  • Alerts to notify administrators about suspicious network events

Each of these ISA technologies can be applied individually or together to address the performance and security challenges faced by company branch offices in terms of accessing information stored on the main office network with improved security, reliability and accessibility.


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Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.