• SonicOS 7.1 Rules and Policies
• Overview
  • About SonicOS
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  • How to Use the SonicOS Administration Guides
  • Guide Conventions
• Settings
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  • Configuring Content Filtering Service (CFS)
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      • Deleting Custom List Entries
    • Using Geo-IP Diagnostics
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  • Decryption (DPI-SSL)
    • Certificate
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• Security Policy
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• NAT Policy
  • About NAT in SonicOS
  • About NAT Load Balancing
    • Determining the NAT LB Method to Use
    • Caveats
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    • Sticky IP Algorithm Examples
      • Example One - Mapping to a Network
      • Example Two - Mapping to an IP Address Range
  • About NAT64
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  • About FQDN-based NAT
  • About Source MAC Address Override
  • Viewing NAT Policy Entries
    • Changing the Display
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  • Adding or Editing NAT or NAT64 Rule Policies
  • Deleting NAT Policies
  • Creating NAT Rule Policies: Examples
    • Creating a One-to-One NAT Policy for Inbound Traffic
    • Creating a One-to-One NAT Policy for Outbound Traffic
    • Inbound Port Address Translation via One-to-One NAT Policy
    • Inbound Port Address Translation via WAN IP Address
    • Creating a Many-to-One NAT Policy
    • Creating a Many-to-Many NAT Policy
    • Creating a NAT Load Balancing Policy for Two Web Servers
• Routing
  • About Routing
    • About Metrics and Administrative Distance
      • About Metrics
      • About Administrative Distance
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    • OSPF and RIP Advanced Routing Services
      • About Routing Services
        • Protocol Type
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        • Subnet Sizes Supported
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      • OSPF Terms
    • Drop Tunnel Interface
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  • Rules and Policies >
    • Configuring
      • Adding Static Routes
      • Probe-Enabled Policy-based Routing Configuration
• Decryption Policy
  • Client-side SSL Rules
  • Server-side SSL Rules
  • SSH Rules
  • Setting up the Decryption Policy Table
    • Managing the Decryption Policy Toolbars
    • Changing the Policy Priority
    • Creating Decryption Policies
      • Adding Decryption Policies
      • Editing Decryption Policies
      • Deleting Decryption Policies
• DoS Policy
  • Setting up the DoS Policy Table
    • Managing the DoS Policy Toolbars
    • Changing the DoS Policy Priority
    • Creating DoS Policies
      • Adding DoS Policies
      • Editing DoS Policies
      • Deleting DoS Policies
• DNS Policy
  • Creating DNS Policies
    • Adding DNS Policies
    • Editing DNS Policies
    • Deleting DNS Policies
  • DNS Doctoring
• Endpoint Policy
• Shadow
• SonicWall Support
  • About This Document

About NAT in SonicOS

Before configuring NAT policies, be sure to create all address objects associated with the policy. For instance, if you are creating a one-to-one NAT policy, be sure you have address objects for your public and private IP addresses.

By default, LAN to WAN has a NAT policy predefined on the firewall.

The Network Address Translation (NAT) engine in SonicOS allows you to define granular NAT policies for your incoming and outgoing traffic. By default, the firewall has a preconfigured NAT policy to allow all systems connected to the X0 interface to perform many-to-one NAT using the IP address of the X1 interface, and a policy to not perform NAT when traffic crosses between the other interfaces. NAT policies are automatically created when certain features are enabled, such as the Enable Local Radius Server option in WLAN zone configuration, and are deleted when the feature is disabled. This section explains how to set up the most common NAT policies.

Understanding how to use NAT policies starts with examining the construction of an IP packet. Every packet contains addressing information that allows the packet to get to its destination, and for the destination to respond to the original requester. The packet contains (among other things) the requester’s IP address, the protocol information of the requester, and the destination’s IP address. The NAT Policies engine in SonicOS can inspect the relevant portions of the packet and can dynamically rewrite the information in specified fields for incoming, as well as outgoing traffic.

You can add up to 512 - 2048 NAT policies depending on the SonicWall network security platform, and they can be as granular as you need. It is also possible to create multiple NAT policies for the same object — for instance, you can specify that an internal server use one IP address when accessing Telnet servers, and to use a totally different IP address for all other protocols. Because the NAT engine in SonicOS supports inbound port forwarding, it is possible to hide multiple internal servers off the WAN IP address of the firewall. The more granular the NAT policy, the more precedence it takes.