AirMarshal is a web based authentication server or captive portal

Captive portal

The captive portal technique forces an HTTP client on a network to see a special web page before using the Internet normally. A captive portal turns a Web browser into an authentication device. This is done by intercepting all packets, regardless of address or port, until the user opens a browser...

 for ethernet based networks. Similar technology is in use popularly to control access to many of today's Internet HotSpots. While Air Marshal is sold commercially the software is free to smaller network operators for up to 5 simultaneously logged on users.

Feature Summary

• Network authentication, authorization and accounting are provided via the RADIUS
  RADIUS
  Remote Authentication Dial In User Service is a networking protocol that provides centralized Authentication, Authorization, and Accounting management for computers to connect and use a network service...
  
  /AAA
  AAA protocol
  In computer security, AAA commonly stands for authentication, authorization and accounting.- Authentication :Authentication refers to the process where an entity's identity is authenticated, typically by providing evidence that it holds a specific digital identity such as an identifier and the...
  
   protocol.

• A variety of network topologies are supported by Air Marshal including Layer 3 routing
  Routing
  Routing is the process of selecting paths in a network along which to send network traffic. Routing is performed for many kinds of networks, including the telephone network , electronic data networks , and transportation networks...
  
  , NAT
  Network address translation
  In computer networking, network address translation is the process of modifying IP address information in IP packet headers while in transit across a traffic routing device....
  
   and Layer 2 transparent bridging.

Release Chronology

• March 2003 - Version 1 - first commercial release.

• May 2006 - Final maintenance release of the version 1 series.

• August 2007 - Version 2 - released as a free upgrade with more than 30 new features.