Virtual Private Networks (VPN’s) By: Agasi Aslanyan Joel Almasol Joe Nghe Michael Wong CIS 484 May 20, 2004

Table Of Contents VPN Introduction – What is VPN and who uses it? 3 Types of VPN’s VPN Protocols VPN Tunneling VPN Packet Transmission VPN Security: Firewalls VPN Devices VPN Advantages/Disadvantages VPN Connections in Windows XP Summary/Conclusion

What is a VPN? A virtual private network (VPN) is a network that uses public means of transmission (Internet) as its WAN link

What is a VPN? (Cont.) A VPN can be created by connecting offices and single users (including mobile users) to the nearest service providers POP (Point of Presence) and using that service provider’s backbone network, or even the Internet, as the tunnel between offices Traffic that flows through the backbone is encrypted to prevent intruders from spying or intercepting the data

What is a VPN? (Cont.)

Who uses VPN’s? VPN’s can be found in homes, workplaces, or anywhere else as long as an ISP (Internet Service Provider) is available. VPN’s allow company employees who travel often or who are outside their company headquarters to safely and securely connect to their company’s Intranet

3 Types of VPN Remote-Access VPN Site-to-Site VPN (Intranet-based) Site-to-Site VPN (Extranet-based)

Remote-Access VPN Remote-access, also called a virtual private dial-up network (VPDN), is a user-to-LAN connection used by a company that has employees who need to connect to the private network from various remote locations. A good example of a company that needs a remote-access VPN would be a large firm with hundreds of sales people in the field. Remote-access VPNs permit secure, encrypted connections between a company's private network and remote users through a third-party service provider.

Site-to-Site VPN Intranet-based - If a company has one or more remote locations that they wish to join in a single private network, they can create an intranet VPN to connect LAN to LAN. Extranet-based - When a company has a close relationship with another company (for example, a partner, supplier or customer), they can build an extranet VPN that connects LAN to LAN, and that allows all of the various companies to work in a shared environment.

All 3 types of VPN

VPN Protocols There are three main protocols that power the vast majority of VPN’s: PPTP L2TP IPsec All three protocols emphasize encryption and authentication; preserving data integrity that may be sensitive and allowing clients/servers to establish an identity on the network

VPN Protocols (In depth) Point-to-point tunneling protocol (PPTP) PPTP is widely supported by Microsoft as it is built into the various flavors of the Windows OS PPTP initially had weak security features, however, Microsoft continues to improve its support Layer Two tunneling protocol (L2TP) L2TP was the original competitor to PPTP and was implemented primarily in Cisco products L2TP is a combination of the best features of an older protocol L2F and PPTP L2TP exists at the datalink layer (Layer 2) of the OSI model

VPN Protocols (continued) Internet Protocol Security Protocol (IPSec) provides enhanced security features such as better encryption algorithms and more comprehensive authentication. IPSec has two encryption modes: tunnel and transport. Tunnel encrypts the header and the payload of each packet while transport only encrypts the payload. Only systems that are IPSec compliant can take advantage of this protocol. IPSec can encrypt data between various devices, such as: Router to router Firewall to router PC to router PC to server

VPN Tunneling VPN Tunneling supports two types: voluntary tunneling and compulsory tunneling Voluntary tunneling is where the VPN client manages the connection setup. Compulsory tunneling is where the carrier network provider manages the VPN connection setup.

Tunneling Most VPNs rely on tunneling to create a private network that reaches across the Internet. Essentially, tunneling is the process of placing an entire packet within another packet and sending it over a network. Tunneling requires three different protocols: Passenger protocol - The original data (IPX, IP) being carried Encapsulating protocol - The protocol (GRE, IPSec, L2F, PPTP, L2TP) that is wrapped around the original data Carrier protocol - The protocol used by the network that the information is traveling over

VPN Packet Transmission Packets are first encrypted before sent out for transmission over the Internet. The encrypted packet is placed inside an unencrypted packet. The unencrypted outer packet is read by the routing equipment so that it may be properly routed to its destination Once the packet reaches its destination, the outer packet is stripped off and the inner packet is decrypted

VPN Security: Firewalls A well-designed VPN uses several methods for keeping your connection and data secure: Firewalls Encryption IPSec AAA Server You can set firewalls to restrict the number of open ports, what type of packets are passed through and which protocols are allowed through.

Cisco 1700 Series Routers Some VPN products, such as Cisco 1700 routers, can be upgraded to include firewall capabilities by running the appropriate Cisco IOS on them.

VPN Concentrator Incorporating the most advanced encryption and authentication techniques available, Cisco VPN concentrators are built specifically for creating a remote-access VPN. The concentrators are offered in models suitable for everything from small businesses with up to 100 remote-access users to large organizations with up to 10,000 simultaneous remote users.

Advantages of VPN’s There are two main advantages of VPN’s, namely cost savings and scalability VPN’s lower costs by eliminating the need for expensive long-distance leased lines. A local leased line or even a broadband connection is all that’s needed to connect to the Internet and utilize the public network to securely tunnel a private connection

Advantages of VPN’s (continued) As the number of company branches grows, purchasing additional leased-lines increases cost exponentially, which is why VPN’s offer even greater cost savings when scalability is an issue VPN’s may also be used to span globally, which lowers cost even more when compared to traditional leased lines

Disadvantages of VPN’s Because the connection travels over public lines, a strong understanding of network security issues and proper precautions before VPN deployment are necessary VPN connection stability is mainly in control of the Internet stability, factors outside an organizations control Differing VPN technologies may not work together due to immature standards

VPN Connection in XP

Summary A virtual private network (VPN) is a network that uses public means of transmission (Internet) as its WAN link, connecting clients who are geographically separated through secure tunneling methods Main VPN protocols include PPTP, L2TP, and IPsec VPN Tunneling supports two types: voluntary tunneling and compulsory tunneling Cost and Scalability are the main advantages of a VPN Network security and Internet stability are the main concerns for VPN’s

Resources Used http://vpn.shmoo.com/ http://www.uwsp.edu/it/vpn/ http://info.lib.uh.edu/services/vpn.html http://www.cites.uiuc.edu/vpn/ http://www.positivenetworks.net/images/client-uploads/jumppage2.htm

The End Thank you all for your time. We hope you found this presentation informative.