Types of VPNs
¨May be encrypted
(IPsec) or nonencrypted (GRE)
¨May be formed using
Frame Relay or ATM
¨Network layer VPNs
include IPsec, GRE, and L2TP
¨Application layer
VPNs include SSL and SSH
¨Intranet VPNs
connect two or more private networks
within the same organization
¨Extranet VPNs connect private networks belonging to more than one organization