remote access service (RAS)

RAS was a service provided by Windows NT which allows most of the services which would be available on a network to be accessed over a modem link. The service includes support for dialup and logon, and then presents the same network interface as the normal network drivers. It is not necessary to run Windows NT on the client - there are client versions for other Windows operating systems.

A feature built into Windows NT that enables users to log into an NT-based LAN using a modem, X.25 connection or WAN link. RAS works with several major network protocols, including TCP/IP, IPX, and NBF.

for example

when the user needs to connect to the lan at the office time to time from remote location the RAS has to configured at the office.the RAS has attached to the modem and a fixed phoneline.once the remote user dials to the phone number of RAS using his dialup connection the RAS accepts the call and validate user credential.if the user is authorised he is allowed to connect to the office lan.

callback

in remote access,the callback option is allow the RAS to called back to the remote user once the account validated.there are 2 options,

• set by a caller

the remote user will be callback by the RAS to any number the user has called from.

• always callback to

in this option RAS calls back to a predefined number set under the user account.no matter which number the user calls from.