Virtual Private Network (VPN) is an internal network that is established between two or more end points via the Internet or other media. VPN creates a tunnel within the media between two end points. VPN also uses various methods and encryption mechanism to secure the VPN connection. There are different types of VPN protocols available which may suit to you based on your requirement. Virtual private network protocol types are: -
- PPTP: – Point-to-Point Tunneling Protocol (PPTP) is the layer 2 VPN tunneling protocol that relies on Point-to-Point (PPP) protocol. PPTP operates at TCP port number 1723. Virtual Private Network can be configured on Windows or Linux or MAC platform using PPTP protocol.In Windows, PPTP protocol can be configured with conjunction with various authentication protocols for security. Authentication protocols like PAP, CHAP, MS-CHAPv1, MS-CHAPv2 and EAP-TLS can be used in VPN authentication. Microsoft Windows uses Microsoft Point-to-Point Encryption (MPPE) for encrypting the VPN connection while using MS-CHAPv1, MS-CHAPv2 and EAP-TLS as authentication mechanism.
- L2TP: – Layer 2 Tunneling Protocol (L2TP) is layer 2 VPN tunneling protocol. It doesn’t have its own encryption and authentication mechanism. It relies on Internet Protocol security (IPSec) for confidentiality, integrity and authentication. L2TP is a combination of Cisco’s Layer 2 forwarding protocol (L2F) and PPTP. When using L2TP/IPSec for VPN solution, you will require two certificates. One for server and another for client.
- SSTP: – Secure Socket Tunneling Protocol (SSTP) is an application layer tunneling protocol. It uses secure socket layer (SSL) for encryption, authentication and integrity of data by using secure HTTP protocol. So SSTP protocol uses 443 port to operate. SSTP was introduced by Microsoft in server 2008. By this protocol VPNs can be established using HTTPS which much secure and easier to implement. Other application layer VPNs has also been developed by Cisco and Juniper that uses HTTPS for VPN establishment.
- IPSec: – IPSec VPN is very secure and complex in configuring VPN connection. It is configured mostly in site to site type of connection between offices or enterprises. This VPN protocol works on layer 3 of OSI model. In IPSec, traffic protection is provided by two security protocols i.e. Authentication Header (AH) and Encapsulation Security Payload (ESP). AH provides integrity and authentication of data whereas ESP provides confidentiality, integrity and encryption. In real world, IPSec is used by combining the power of both AH and ESP protocol using internet key exchange (IKE) protocol. IKE is used to negotiate, create and manage the connection before and after the connection exists between two points. IKE also negotiates the identities of both VPN end points automatically during predefined interval making VPN connections more secure. IPSec VPN is provided by Juniper’s security gateways.
