Configuring Virtual Private Networks for Remote Clients and Networks

1

Configuring Virtual Private Networks for Remote Clients and Networks

2

What Is Virtual Private Networking?

• Virtual private networking allows secure remote access to resources on an organization’s internal network for users outside the network

• A VPN is a virtual network that enables communication between a remote access client and computers on the internal network or between two remote sites separated by a public network such as the Internet

3

Types of VPNs

• Remote Access VPN– Provides access to

internal corporate network over the Internet

– Reduces long distance, modem bank, and technical support costs

InternetInternet

CorporateSite

4

Types of VPN

• Site-to-Site VPN– Connects multiple

offices over Internet– Reduces

dependencies on frame relay and leased lines

InternetInternet

BranchOffice

Corporate Site

5

Types of VPN• Extranet VPN– Provides business

partners access to critical information (leads, sales tools, etc)

– Reduces transaction and operational costs

CorporateSite

InternetInternet

Partner #1

Partner #2

6

What a VPN needs

• VPNs must be encrypted – so no one can read it

• VPNs must be authenticated• No one outside the VPN can alter the VPN• All parties to the VPN must agree on the security

properties

7

VPN Topology

• Operates at layer 2 or 3 of OSI model– Layer 2 frame – Ethernet– Layer 3 packet – IP

• Tunneling– allows senders to encapsulate their data in IP

packets that hide the routing and switching infrastructure of the Internet

– to ensure data security against unwanted viewers, or hackers

8

VPN Components

Protocols:• IP Security (IPSec)– Transport mode– Tunnel mode

• Point-to-Point Tunneling Protocol (PPTP)– Voluntary tunneling method– Uses PPP (Point-to-Point Protocol)

9

VPN Components

Protocols:• Layer 2 Tunneling Protocol (L2TP)– Exists at the data link layer of OSI– Composed from PPTP and L2F (Layer 2

Forwarding)– Compulsory tunneling method

10

VPN Components

Security:• Authentication– Determine if the sender is the authorized person

and if the data has been redirect or corrupted – User/System Authentication– Data Authentication

11

VPN Components

12

Configuring Virtual Private Networking for Remote Clients

13

Creating a Remote Access PPTP VPN Server

• Enabling the ISA Firewall’s VPN Server component

• Creating an Access Rule allowing VPN Clients access to the Internal network

• Enabling Dial-in Access for VPN User Accounts• Testing a PPTP VPN Connection

14

Enable the VPN Server

Enable VPN Client AccessEnable VPN

Client Access

Warning About address assignment

Warning About address assignment

15

Assigning IP Address Assignment for Remote Users

• Remote users that will be establishing a VPN tunnel require an IP address to properly communicate through the tunnel to the internal network

16

Authenticating VPN Users

• Authenticating directly against Active Directory

• Implement RADIUS Authentication

• Authenticate against local users

17

Working with and Creating Rules for the VPN Clients Network

create default rules that allow VPN clientsaccess into the network

create default rules that allow VPN clientsaccess into the network

18

RADIUS Authentication for VPNConnections

Install the Internet Authentication Service (IAS) for Active Directory RADIUS Support

Install the Internet Authentication Service (IAS) for Active Directory RADIUS Support

19

Setting Up the ISA Server as an IAS Client

Define a RADIUS server shared keyDefine a RADIUS

server shared key

20

Configuring ISA to Use IAS for Authentication

Define a RADIUS server shared key in ISA

Define a RADIUS server shared key in ISA

Modify RADIUS server settings for VPN client

access

Modify RADIUS server settings for VPN client

access

21

Configuring an ISA VPN Connection to Use PPTP

22

Creating Layer 2 Tunneling Protocol (L2TP) VPN

Enter an IPSec pre-shared key.

Enter an IPSec pre-shared key.

23

Creating a Public Key Infrastructure (PKI) for L2TP with IPSec Support

• Installing the Enterprise Root Certificate Authority (CA)

• Configuring the Enterprise Root CA• Requesting a Certificate for the ISA VPN

Server• Requesting a Certificate for the VPN Client• Downloading the CA Certificate• Exporting and Importing Certificates

24

Configuring Virtual Private Networking for Remote Sites

25

Site-to-Site VPN Capabilities

• Point-to-Point Tunneling Protocol (PPTP)• Layer 2 Tunneling Protocol (L2TP)• IPSec Tunnel Mode

26

Preparing ISA Servers for Site-to-Site VPN Capabilities

• Define the IP Address Assignment• Enable VPN client access• Create local VPN user accounts on both

servers, and enable dial-in access for those accounts.

• Run through the Site-to-Site VPN wizard to configure all necessary networks, network rules, and access rules.

• Repeat the steps on the remote server.

27

Create VPN Site-to-Site

28

Configuring a Point-to-Point Tunneling Protocol (PPTP) Site-to-Site VPN Between Two Remote

OfficesCreate a PPTP Site-to-Site VPN

ConnectionCreate a PPTP Site-to-Site VPN

Connection

29

Configuring a Layer 2 Tunneling Protocol (L2TP) Site-to-Site VPN

• Deciding Between Shared Key and PKI• Configuring a PKI Infrastructure for PKI-Based

Certificate Encryption• Requesting a Certificate for the ISA VPN

Server• Creating an L2TP/IPSec Site-to-Site VPN

Connection

30

Setting Up an IPSec Tunnel Mode VPN Connection