Network access server: Difference between revisions

Revision as of 11:27, 28 May 2012

Revision as of 21:35, 31 October 2012

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*An [[Internet Service Provider]] which provides network access via common modem or modem-like devices (be it [[PSTN]], [[DSL]], [[cable modem|cable]] or [[GPRS]]/[[UMTS]]) can have one or more NAS (network access server) devices which accept [[Point-to-Point Protocol|PPP]], [[PPPoE]] or [[PPTP]] connections, checking credentials and recording accounting data via back-end [[RADIUS]] servers, and allowing users access through that connection.

*A sample use is the [[captive portal]] mechanism used by many [[WiFi]] providers: a user wants to access to the Internet. He opens his [[web browser|browser]]. The NAS detects that the user is not currently [[authorized]] to have access to the Internet, so the NAS prompts the user for their username and password. The user supplies them and sends them back to the NAS. The NAS then uses the [[RADIUS]] protocol to connect to an [[AAA protocol|AAA]] server and passes off the [[username]] and [[password]]. The RADIUS server searches through its resources and finds that the credentials are valid and notifies the NAS that it should grant the access. The NAS then grants the user access to the internet.

*Another use of a NAS would be in [[VoIP]]. However, instead of using a username and password, many times a [[phone number]] or [[IP Address]] are used. If the phone number is a valid customer then the call can be completed. Other uses might be if the phone number has [[long distance calling|long distance]] access or if a [[telephone card]] has minutes left.