Notes

VPN stands for Virtual Private Network. it is the arrangement whereby a private or secure network in achieved for the organization using encryption over the public network, typically internet.
explanation: consider that every LAN is like an ocean and every VPN is like a sub-marine in tat ocean. keeping these analogy in mind, VPN has following characteristics: it is fast. it is easy to take you anywhere. it is completely hidden from all the other sub-marines. it is dependable. it will cost you little more to add another sub-marine to your feet. BENEFITS: It provide extended connection over multiple geographical location. Improve security of exchanging data. Flexibility for the business and employee to connect to the corporates private network from remote location. Reduce cost and time for the employee working from remote areas. Increased productivity of employees working from remote areas. TYPES: there are following two types of VPN. 1) Remote Access VPN: it allow the individual user to access the organization private network using the laptop with internet connection, working via remote location. Two requirements for the remote-access VPN are Network Access Server (NAS) and Client software. 2) Site-to-site VPN: allow the branch office of thte organization to use internet as a channel for to access the main office's intranet. there are two types of site-to-site VPN intranet and extranet. Tunneling is the virtual connection over the public network that is established to exchange or transmit the encapsulated header.
EQUIPMENT REQUIRED: IP security (IPSec) => encapsulated security payload(ESP) and Authentication Header(AH). Point-to-Point Protocol (P2P) => Layer 2 forwarding(L2F), Point to point tunneling protocol(PPTP), layer 2 tunneling protocol (L2TP). Network Access Server(NAS), Firewall, AAA server. VPN concentrator, VPN-enabled/optimized router, VPN-enable firewall, VPN client.