Abbreviated as NAS, a
network access server is an access
gateway between an external
communications network and an internal network. A common use of NAS is by Internet service providers (
ISP) where the user dials into the ISP and is given access to the
Internet after being authorized by the access server. Network access server (NAS) is also referred to as a
remote access server (RAS) or as a media gateway. The
IETF Network Access Server Requirements Working Group is responsible for defining the requirements for modern network access servers.