II
7.1 Demands .................................................................................................................................................................. 39
7.2 Objectives ................................................................................................................................................................ 39
7.3 Methods.................................................................................................................................................................... 39
7.4 Steps......................................................................................................................................................................... 40
7.4.1 Block internal PC session (LAN WAN).................................................................................................... 40
7.4.2 Setup Alert detected attack............................................................................................................................. 41
Part III Virtual Private Network ......................................................................................................................44
Chapter 8 VPN Technical Introduction...............................................................................................................45
8.1 Terminology Explanation......................................................................................................................................... 45
8.1.1 VPN................................................................................................................................................................ 45
8.1.2 IPSec............................................................................................................................................................... 45
8.1.3 Security Association....................................................................................................................................... 45
8.1.4 IPSec Algorithms............................................................................................................................................ 45
8.1.5 Key Management............................................................................................................................................ 45
8.1.6 Encapsulation ................................................................................................................................................. 46
8.1.7 IPSec Protocols............................................................................................................................................... 47
8.2 Make VPN packets pass through DFL-900.............................................................................................................. 47
Chapter 9 Virtual Private Network – IPSec.........................................................................................................49
9.1 Demands .................................................................................................................................................................. 49
9.2 Objectives ................................................................................................................................................................ 49
9.3 Methods.................................................................................................................................................................... 49
9.4 Steps......................................................................................................................................................................... 50
9.4.1 DES/MD5 IPSec tunnel: the IKE way............................................................................................................ 50
9.4.2 DES/MD5 IPSec tunnel: the Manual-Key way .............................................................................................. 56
Chapter 10 Virtual Private Network – PPTP.......................................................................................................61
10.1 Demands .................................................................................................................................................................. 61
10.2 Objectives ................................................................................................................................................................ 61
10.3 Methods.................................................................................................................................................................... 61
10.4 Steps......................................................................................................................................................................... 62
Chapter 11 Virtual Private Network – L2TP.......................................................................................................65
11.1 Demands .................................................................................................................................................................. 65
11.2 Objectives ................................................................................................................................................................ 65
11.3 Methods.................................................................................................................................................................... 65
11.4 Steps......................................................................................................................................................................... 66
11.4.1 Setup L2TP Network Server........................................................................................................................... 66
11.4.2 Setup L2TP Network Client ........................................................................................................................... 68
Part IV Content Filters.....................................................................................................................................70
Chapter 12 Content Filtering – Web Filters ........................................................................................................71
12.1 Demands .................................................................................................................................................................. 71
12.2 Objectives ................................................................................................................................................................ 71
12.3 Methods.................................................................................................................................................................... 71
12.4 Steps......................................................................................................................................................................... 72
Chapter 13 Content Filtering – Mail Filters........................................................................................................77
13.1 Demands .................................................................................................................................................................. 77
13.2 Objectives ................................................................................................................................................................ 77