In the Remote Access Service( RAS), the RAS server takes over the access control of the remote users. Via the RAS server, remote users gain access to the corporate network and can work with the available resources and network services.
The RAS server authenticates the caller, can handle multiple dial-up connections simultaneously and provides the communication interfaces over dial-up public fixed networks and mobile networks for this purpose, and provides the connection of the remote user to the corporate network. Connection via RAS servers is mainly used in home offices for telecommuting, for connecting branch offices and for the mobile office; but also when several users access applications on a central server, such as the Microsoft Terminal Server or Citrix Metaframe.
RAS servers, which are increasingly being replaced by IP routers, support TCP/IP, IPX/ SPX or NetBetBEUI transport protocols and tunneling. This replacement can be seen in the change in access. Where dial-up connections used to dominate dial-up to the RAS server, broadband technologies such as Digital Subscriber Line( DSL) are increasingly being used. Likewise, the trend toward virtual private networks( VPN) is unmistakable.