ZyXEL Communications 10, 50 FIREWALL AND CONTENT FILTERS

		ZYWALL 10/50 Internet Security Gateway
9.1.5		NAT Mapping Types..........................................................................................................	9-4
9.2	Using NAT .................................................................................................................................		9-6
9.2.1		SUA (Single User Account) Versus NAT ..........................................................................	9-6
9.2.2		Applying NAT....................................................................................................................	9-6
9.3	NAT Setup..................................................................................................................................		9-8
9.3.1		Address Mapping Sets........................................................................................................	9-8
9.4 NAT Server Sets – Port Forwarding.........................................................................................			9-13
9.4.1		Configuring a Server behind NAT ...................................................................................	9-14
9.5	General NAT Examples ...........................................................................................................		9-16
9.5.1		Internet Access Only ........................................................................................................	9-16
9.5.2		Example 2: Internet Access with an Inside Server ...........................................................	9-17
9.5.3		Example 3: Multiple Public IP Addresses With Inside Servers........................................	9-18
9.5.4		Example 4: NAT Unfriendly Application Programs ........................................................	9-22
FIREWALL AND CONTENT FILTERS ....................................................................................................			III
Chapter 10 Firewalls..............................................................................................................................			10-1
10.1		What Is a Firewall?...............................................................................................................	10-1
10.2		Types of Firewalls ................................................................................................................	10-1
10.2.1		Packet Filtering Firewalls.................................................................................................	10-1
10.2.2		Application-level Firewalls ..............................................................................................	10-1
10.2.3		Stateful Inspection Firewalls ............................................................................................	10-2
10.3		Introduction to ZyXEL’s Firewall........................................................................................	10-2
10.4		Denial of Service ..................................................................................................................	10-3
10.4.1		Basics ...............................................................................................................................	10-3
10.4.2		Types of DoS Attacks.......................................................................................................	10-4
10.5		Stateful Inspection................................................................................................................	10-7
10.5.1		Stateful Inspection Process...............................................................................................	10-8
10.5.2		Stateful Inspection and the ZyWALL...............................................................................	10-9
10.5.3		TCP Security ..................................................................................................................	10-10

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