Organizations generally have remote users who are on the public internet, and are required to access the corporate resources while on the move. This requires the DC to be connected to the internet, and allow the access of the servers in the intranet to the end users.
Although the DC is directly connected to the internet and separate servers can be hosted in the DMZ to allow this access, this would not be secure, as these servers would then be exposed to the complete internet. Such access is provided by bringing the remote users on the internal networks through VPNs, and then treating them as a part of the internal networks. The remote access VPNs (RAVPNs) are created over IP networks, typically the internet infrastructure and are secured using IPSec. The VPNs are authenticated using the credentials of the users to ensure that only the authorized...