There are basically four types of VPNs:
A firewall-based VPN is equipped with both a firewall and VPN capabilities. This type uses the security provided by firewalls to restrict access to an internal network and provides address translation, user authentication, alarms and logging.
A hardware-based VPN provides high network throughput as well as improved performance and reliability, but is also expensive.
A software-based VPN provides flexibility in terms of how traffic is managed. This is best for when endpoints are not controlled by the same party and when different firewalls and routers are used.
A secure socket layer (SSL) VPN enables users to connect to VPN devices using a web browser. SSL is used to encrypt traffic between the web browser and the VPN device.
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