A01 chaf6542 06 se fm indd

Virtual private networks

A 

virtual private network (VPN)

 is a private  wide-  area network that runs over the public 

network, rather than a more expensive private network. The technique by which VPN oper-

ates is sometimes referred to as ‘tunnelling’, and involves encrypting both packet headers 

and content using a secure form of the Internet Protocol known as IPSec. As explained in 

Chapter 3, VPNs enable the global organisation to conduct its business securely, but using 

the public Internet rather than more expensive proprietary systems.