VPN by Jigar Lad

Virtual Private NetworksINSTITUTE OF FORENSIC SCIENCE , GFSU

JIGAR LAD

What is A VPN?

A virtual private network (VPN) is the extension of a private network that encompasses links across shared or public networks like the Internet.

It provides LAN access to end systems not physically located on the LAN

An alternative to WAN (Wide Area Networks) which use leased lines to connect

A typical VPN might have a main LAN at the corporate headquarters of a company, other LANs at remote offices or

facilities and individual users connecting from out in the field.

How does it work?

Data is encrypted (cannot be deciphered without the key)

Virtual Point to Point Connection To the user, it acts like a point to point connection

Data is packaged with a header

Benefits of Using VPN

Expand Globally Costs reduced

No dedicated lines necessary

Easier Technology is on the end systems, which

makes it more scalable No single point of failure Easier Network Management

Types of VPN

Two Types: Site to Site VPN

Remote Access VPN

Remote Access VPN

Essentially provides LAN access through dial-up connection Typically done by purchasing a NAS (Network

Access Server) with a toll free number

Can instead be done through normal ISP connection using the VPN software to make a virtual connection to the LAN

Site to Site VPN

Connects two LANs over local ISP connections

Very useful if you need to connect a branch to a main hub (Big business)

Much less expensive than purchasing one dedicated line between the hub and branch

Intranet connects remote locations from one company

Extranet connects two companies (partners) into one shared Private Network

Security

Many types of Security are offered including: Firewalls

Encryption

IPSec

Certificates

AAA servers

Firewalls

Can be used with VPN is right technology is set up on the router Cisco 1700 router for example

Can restrict: The type of data being transferred

The number of ports open

Which protocols are allowed through

Encryption

Symmetric Key Encryption (private key) All communicating computers use the same key

stored on their computer

Asymmetric Key Encryption Uses a Private key and a Public Key

Private key on local computer

Public key sent out to anyone who you want to communicate with

Mathematically related through encryption algorithm

Both must be used to decrypt anything sent

IPSec

Made up of two parts Authentication Header

Verify data integrity

Encapsulation Security Payload

Data integrity

Data encryption

IPSec continued

Authentication Header Authentication Data Sequence number

Encapsulating Security Payload Encrypt data Another layer of integrity and

authentication checks

Certificates

Used alongside public keys Contains:

Certificate Name Owner of the public key Public key itself Expiration date Certificate authority

Verifies that information is coming from the private key

Can be distributed on disks, smart cards, or electronically

AAA Servers

Authentication, Authorization, Accounting These advanced servers ask each user who they

are, what they are allowed to do, and what the actually want to do each time they connect

This allows the LAN to track usage from dial up connections and closely monitor those remotely connected as they would those physically connected.