Securing a geographically distributed network: An example design

Information Technologies (IT s) are making possible the integration of different information systems used by geographically dispersed organizations. An integration model must facilitate the combination of internet, intranet and extranet concepts with a high fiability security policy and it ought to be perfectly adapted to the organizational structure. An adequate security policy must consider the establishment of a Virtual Private Network (VPN) identifying different potential clients: clients connected to the intranet by modem, by isdn, etc; clients connected to the VPN; or teleworking stations accessing through the extranet. Thus, this study aims to define the function of all those elements which provide security in an VPN such as firewalls and encryptation systems and to reduce the vulnerability of the elements taking part in an information exchange.