B2B Integration : A Practical Guide to Collaborative E-commerce

Internet Security 309
Virtual private networks enable enterprises to leverage the Internet,
while protecting sensitive business information. With VPNs, companies
can achieve a significant cost saving of up to 60% over private leased
lines and 30% over frame-relay networks.
VPNs have to provide scalability, flexibility and reliable performance
in order that the companies use them to support access to their missioncritical
applications. All the components of VPNs should be easy to
configure and provide seamless integration within the whole enterprise
security infrastructure.
VPNs have to provide the following three critical functions to
ensure security for data:
• Authenticate — confirm that the data is coming from the source that
it claims;
• Secure — restrict read/write access and maintain data integrity of the
data traveling over the Internet; and
• Access control — allow only authorized users to gain admission to
the network
VPN uses the following technologies:
• Encryption;
• Authentication; and
• Protocol Tunneling — In protocol tunneling, the actual data packets
are encrypted; then enclosed inside other IP packets and transmitted
across the Internet. At the destination, there is a special host that
decrypts them. This tunneling of data is completely transparent to the
end-users. They feel as if they are directly connected to the internal
LAN.
Various protocols are used to carry out tunneling, such as Microsoft's
Point-to-Point Tunneling Protocol (PPTP), Ipsec protocol and L2TP
protocol proposed by Cisco and Microsoft. There are several vendor
products available for creating and managing VPNs, such as IBM
eNetwork VPN series and AltaVista Tunnel97. Many telecom carriers
such as AOL and AT&T also offer dedicated services for VPN
communication.