• SonicOS 7.1 Rules and Policies
• Overview
  • About SonicOS
  • SonicOS Workflow
  • How to Use the SonicOS Administration Guides
  • Guide Conventions
• Access Rules
  • Setting Firewall Access Rules
    • About Connection Limiting
    • Using Bandwidth Management with Access Rules
      • Enabling Bandwidth Management on an Access Rule
    • Creating Access Rules
    • Configuring Access Rules for IPv6
      • About Stateful Packet Inspection Default Access Rules
    • Enabling and Disabling Access Rules
    • Editing Access Rules
    • Deleting Access Rules
    • Restoring Access Rules to Default Settings
    • Displaying Access Rules
      • By Zones
      • By Column
    • Displaying Access Rule Traffic Statistics
    • Configuring Access Rules for NAT64
    • Configuring Access Rules for a Zone
    • Access Rules for DNS Proxy
    • User Priority for Access Rules
  • Access Rule Configuration Examples
    • Enabling Ping
    • Blocking LAN Access for Specific Services
    • Allowing WAN Primary IP Access from the LAN Zone
• NAT Rules
  • About NAT in SonicOS
  • About NAT Load Balancing
    • Determining the NAT LB Method to Use
    • Caveats
    • How Load Balancing Algorithms are Applied
    • Sticky IP Algorithm Examples
      • Example One - Mapping to a Network
      • Example Two - Mapping to an IP Address Range
  • About NAT64
    • Use of Pref64::/n
  • About FQDN-based NAT
  • About Source MAC Address Override
  • Viewing NAT Policy Entries
    • Changing the Display
    • Filtering the Display
    • Displaying Information about Policies
  • 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 One-to-Many NAT Load Balancing Policy
    • Creating a NAT Load Balancing Policy for Two Web Servers
    • Creating a WAN-to-WAN Access Rule for a NAT64 Policy
    • DNS Doctoring
• Routing
  • About Routing
    • About Metrics and Administrative Distance
      • About Metrics
      • About Administrative Distance
    • Route Advertisement
    • ECMP Routing
    • Policy-based Routing
    • Policy-based TOS Routing
    • PBR Metric-based Priority
    • Policy-based Routing and IPv6
    • OSPF and RIP Advanced Routing Services
      • About Routing Services
        • Protocol Type
        • Maximum Hops
        • Split-Horizon
        • Poison Reverse
        • Routing Table Updates
        • Subnet Sizes Supported
        • Autonomous System Topologies
      • OSPF Terms
    • Drop Tunnel Interface
    • App-based Routing
  • Rules and Policies >
    • Configuring
      • Adding Static Routes
      • Probe-Enabled Policy-based Routing Configuration
• DNS Rules
  • Creating DNS Filtering Profiles
  • Configuring DNS Filtering
    • Creating DNS Policy Rules
      • Editing DNS Policies
      • Deleting DNS Policies
    • Configuring Global DNS Filtering Settings
    • Configuring DNS Filtering Custom Domains
  • Viewing DNS Information
    • Viewing DNS Using the Dashboard
    • Viewing DNS Filtering Reports
• Content Filter Rules
  • About Content Filtering Rules (CFS)
    • About Content Filter Rules
    • About UUIDs for CFS Policies
    • About Content Filter Action Objects
    • How CFS Works
  • Configuring CFS Policies
    • About the Content Filter Rule Table
      • Searching the Content Filter Rule Table
    • Adding a Content Filter Rule
    • Editing a Content Filter Rule
    • Deleting Content Filter Rules
• App Rules
  • About App Rules
    • What are App Rules?
      • About App Rules Policies
      • About App Rules Capabilities
    • Benefits of App Rules
    • How Does Application Control Work?
    • About App Rules Policy Creation
    • Licensing App Rules and App Control
    • Terminology
  • Rules and Policies > App Rules
    • Configuring an App Rules Policy
  • Verifying App Rules Configuration
    • Useful Tools
      • Wireshark
      • Hex Editor
  • App Rules Use Cases
    • Creating a Regular Expression in a Match Object
    • Policy-based Application Rules
    • Logging Application Signature-based Policies
    • Compliance Enforcement
    • Server Protection
    • Hosted Email Environments
    • Email Control
    • Web Browser Control
    • HTTP Post Control
    • Forbidden File Type Control
    • ActiveX Control
    • FTP Control
      • Blocking Outbound Proprietary Files Over FTP
      • Blocking Outbound UTF-8 / UTF-16 Encoded Files
      • Blocking FTP Commands
    • Bandwidth Management
    • Bypass DPI
    • Custom Signature
    • Reverse Shell Exploit Prevention
      • Generating the Network Activity
      • Capturing and Exporting the Payload to a Text File Using Wireshark
      • Creating a Match Object
      • Defining the Policy
• Endpoint Rules
• SonicWall Support
  • About This Document

Hex Editor

You can use a hexadecimal (hex) editor to view the hex representation of a file or a graphic image. One such hex editor is XVI32, developed by Christian Maas and available at no cost at the following URL:

http://www.chmaas.handshake.de/delphi/freeware/xvi32/xvi32.htm

For example, if there is a certain graphic contained within all confidential company documents, you could use the hex editor to obtain a unique identifier for the graphic, and then use the identifying hex string to create a match object. You could reference the match object in a policy that blocks the transfer of files with content matching that graphic.

To create a match object for a graphic using the SonicWall graphic as an example

1. Start XVI32 and click File > Open to open the graphic image GIF file.

   

2. In the left pane, mark the first 50 hex character block by selecting Edit > Block <n> chars… and then select the decimal option and type 50 in the space provided. This will mark the first 50 characters in the file, which is sufficient to generate a unique thumbprint for use in a custom match object.

   Alternatively you can mark the block by using the following sequence:

   • Click on the first character (#0).
   • Press Ctrl+B.
   • Click on the character in position #49.
   • Press Ctrl+B.

   To locate the character in position #49, click on a character in the right pane (the text pane) and then look at the bottom left corner for the decimal address. Try different characters until it shows Adr. dec: 49.

   You must click on the corresponding location in the left pane before you press Ctrl+B to mark the block.

   When the block is marked, it changes to red font. To unmark a block of characters, press Ctrl+U.

   

3. After you mark the block, click Edit > Clipboard > Copy As Hex String.

4. In a multi-featured text editor, press Ctrl+V to paste the selection and then press Enter to end the line.

   This intermediary step is necessary to allow you to remove spaces from the hex string.

5. In the text editor, click Search > Replace to bring up the Replace dialog box. In the Replace dialog box, type a space into the Find text box and leave the Replace text box empty. Click Replace All.

   The hex string now has 50 hex characters with no spaces between them.

6. Double-click the hex string to select it, then press Ctrl+C to copy it to the clipboard.

7. In the SonicOS user interface, navigate to Objects > Match Objects and click Add Match Object.

8. In the Match Object Settings dialog, type a descriptive name into the Object Name field.

9. In the Match Object Type drop-down menu, select Custom Object.

10. For Input Representation, click Hexadecimal.

11. In the Content field, press Ctrl+V to paste the contents of the clipboard.

12. Click Add.

13. Click OK.

    You now have a Match Object containing a unique identifier for the image. You can create an App Rules policy to block or log traffic that contains the image matched by this Match Object. For information about creating a policy, see Configuring an App Rules Policy.