Create a Security Policy Rule

  1. (
    Optional
    ) Delete the default Security policy rule.
    By default, the firewall includes a security rule named
    rule1
    that allows all traffic from Trust zone to Untrust zone. You can either delete the rule or modify the rule to reflect your zone naming conventions.
  2. Add a rule.
    1. Select
      Policies
      Security
      and
      Add
      a new rule.
    2. In the
      General
      tab, enter a descriptive
      Name
      for the rule.
    3. Select a
      Rule Type
      .
  3. Define the matching criteria for the source fields in the packet.
    1. In the
      Source
      tab, select a
      Source Zone
      .
    2. Specify a
      Source IP Address
      or leave the value set to
      any
      .
    3. Specify a Source
      User
      or leave the value set to
      any
      .
  4. Define the matching criteria for the destination fields in the packet.
    1. In the
      Destination
      tab, set the
      Destination Zone
      .
    2. Specify a
      Destination IP Address
      or leave the value set to
      any
      .
      As a best practice, use address objects as the
      Destination Address
      to enable access to only specific servers or specific groups of servers especially for commonly exploited services, such as DNS and SMTP. By restricting users to specific destination server addresses, you can prevent data exfiltration and command-and-control traffic from establishing communication through techniques such as DNS tunneling.
  5. Specify the application that the rule will allow or block.
    As a best practice, always use application-based security policy rules instead of port-based rules and always set the Service to application-default unless you are using a more restrictive list of ports than the standard ports for an application.
    1. In the
      Applications
      tab,
      Add
      the
      Application
      you want to safely enable. You can select multiple applications or you can use application groups or application filters.
    2. In the
      Service/URL Category
      tab, keep the Service set to
      application-default
      to ensure that any applications that the rule allows are allowed only on their standard ports.
  6. (
    Optional
    ) Specify a URL category as match criteria for the rule.
    In the
    Service/URL Category
    tab, select the
    URL Category
    .
    If you select a URL category, only web traffic will match the rule and only if the traffic is destined for that specified category.
  7. Define what action you want the firewall to take for traffic that matches the rule.
    In the
    Actions
    tab, select an
    Action
    . See Security Policy Actions for a description of each action.
  8. Configure the log settings.
    • By default, the rule is set to
      Log at Session End
      . You can disable this setting if you don’t want any logs generated when traffic matches this rule or you can select
      Log at Session Start
      for more detailed logging.
    • Select a
      Log Forwarding
      profile.
    As a best practice, do not select the check box to
    Disable Server Response Inspection
    (DSRI). Selecting this option prevents the firewall from inspecting packets from the server to the client. For the best security posture, the firewall must inspect both the client-to-server flows and the server-to-client flows to detect and prevent threats.
  9. Attach security profiles to enable the firewall to scan all allowed traffic for threats.
    Make sure you create best practice security profiles that help protect your network from both known and unknown threats.
    In the
    Actions
    tab, select
    Profiles
    from the
    Profile Type
    drop-down and then select the individual security profiles to attach to the rule.
    Alternatively, select
    Group
    from the
    Profile Type
    drop-down and select a security
    Group Profile
    to attach.
  10. Click
    Commit
    to save the policy rule to the running configuration on the firewall.
  11. To verify that you have set up your basic security policies effectively, test whether your security policy rules are being evaluated and determine which security policy rule applies to a traffic flow.
    The output displays the best rule that matches the source and destination IP address specified in the CLI command.
    For example, to verify the policy rule that will be applied for a server in the data center with the IP address 208.90.56.11 when it accesses the Microsoft update server:
    1. Select
      Device
      Troubleshooting
      , and select
      Security Policy Match
      from the Select Test drop-down.
    2. Enter the Source and Destination IP addresses.
    3. Enter the Protocol.
    4. Execute
      the security policy match test.
    create-security-rule-example.png
  12. After waiting long enough to allow traffic to pass through the firewall, View Policy Rule Usage to monitor the policy rule usage status and determine the effectiveness of the policy rule.

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