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 click
      Add
      .
    2. Enter a descriptive
      Name
      for the rule in the
      General
      tab.
    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, consider using address objects in the
      Destination Address
      field to enable access to specific servers or groups of servers only, particularly for services such as DNS and SMTP that are commonly exploited. 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 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
      to safely enable. You can select multiple applications, or 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 the rule allows are only allowed 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 to the 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 clear this setting if you don’t want any logs generated when traffic matches this rule, or 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.
    See Create Best Practice Security Profiles to learn how to create security profiles that 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. Save the policy rule to the running configuration on the firewall.
    Click
    Commit
    .
  11. To verify that you have set up your basic policies effectively, test whether your security policy rules are being evaluated and determine which security policy rule applies to a traffic flow.
    To verify the policy rule that matches a flow, use the following CLI command:
    test
    security-policy-match source
    <IP_address>
    destination
    <IP_address>
    destination port
    <port_number>
    protocol
    <protocol_number>
    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:
    test security-policy-match source 208.80.56.11 destination 176.9.45.70 destination-port 80 protocol 6
    "Updates-DC to Internet" { from data_center_applications; source any; source-region any; to untrust; destination any; destination-region any; user any; category any; application/service[dns/tcp/any/53 dns/udp/any/53 dns/udp/any/5353 ms-update/tcp/any/80 ms-update/tcp/any/443]; action allow; terminal yes;

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