Dell SonicWALL NSA E6500 Getting Started Manual

Contents

Creating a NAT PolicyThe Network Address Translation (NAT) engine in SonicOSallows users to define granular NAT policies for their incomingand outgoing traffic. By default, the Dell SonicWALL appliancehas a preconfigured NAT policy to allow all systems connectedto the LAN interface to perform Many-to-One NAT using the IPaddress of the WAN interface, and a policy to not perform NATwhen traffic crosses between the other interfaces.You can create multiple NAT policies on a Dell SonicWALLappliance running SonicOS for the same object – for instance,you can specify that an internal server use one IP address whenaccessing Telnet servers, and to use a totally different IPaddress for all other protocols. Because the NAT engine inSonicOS supports inbound port forwarding, it is possible to hidemultiple internal servers off the WAN IP address of the DellSonicWALL appliance. The more granular the NAT Policy, themore precedence it takes.Before configuring NAT Policies, you must create all AddressObjects associated with the policy. For instance, if you arecreating a One-to-One NAT policy, first create Address Objectsfor your public and private IP addresses.Address Objects are one of four object classes (Address, User,Service and Schedule) in SonicOS. These Address Objectsallow for entities to be defined one time, and to be re-used inmultiple referential instances throughout the SonicOS interface.For example, take an internal Web server with an IP address of67.115.118.80. Rather than repeatedly typing in the IP addresswhen constructing Access Rules or NAT Policies, AddressObjects allow you to create a single entity called “My WebServer” as a Host Address Object with an IP address of67.115.118.80. This Address Object, “My Web Server”, can thenbe easily and efficiently selected from a drop-down menu in anyconfiguration screen that employs Address Objects as adefining criterion.Since there are multiple types of network address expressions,there are currently the following Address Objects types:• Host— Host Address Objects define a single host by its IPaddress.• Range— Range Address Objects define a range ofcontiguous IP addresses.• Network— Network Address Objects are like Range objectsin that they comprise multiple hosts, but rather than beingbound by specified upper and lower range delimiters, theboundaries are defined by a valid netmask.• MAC Address— MAC Address Objects allow for theidentification of a host by its hardware address or MAC (MediaAccess Control) address.• FQDN Address— FQDN Address Objects allow for theidentification of a host by its Fully Qualified Domain Names(FQDN), such as www.sonicwall.com.