Configure Transparent Bridge Security Chains

A layer 1 Transparent Bridge security chain forwards traffic from one firewall interface through a directly connected series of data inspection and processing security devices and then back through a different firewall interface without the need to route the traffic.
Before you configure a layer 1 Transparent Bridge security chain, take the steps to Prepare to Deploy Network Packet Broker and ensure that the physical connections between the firewall and the security chain devices are correct.
To distribute sessions across multiple Transparent Bridge security chains, create one layer 1 Transparent Bridge security chain on the firewall for each of the security chains you want to use to load balance traffic. Each Transparent Bridge security chain on the firewall requires two dedicated layer 3 Ethernet interfaces. Check to ensure that you have enough free Ethernet interfaces for the topology you want to configure.
Layer 1 Transparent Bridge security chains cannot failover to another security chain because they are not routed.
  1. Enable two Layer 3 Ethernet interfaces as Network Packet Broker forwarding interfaces.
    1. Select
      Network
      Interfaces
      Ethernet
      .
    2. Select an unused Ethernet interface to use as one of the two Network Packet Broker forwarding interfaces.
    3. Set the
      Interface Type
      to
      Layer3
      .
    4. On the
      Config
      tab, select a zone to assign the interface to.
      You must configure both of the security chain interfaces in the same zone.
    5. On the
      Config
      tab, as a best practice, use or create a dedicated Virtual Router to assign the interface to. Using a dedicated Virtual Router ensures that the Network Packet Broker interface traffic remains separate from other traffic.
    6. Select
      Advanced
      and then select
      Network Packet Broker
      to enable the interface.
    7. Click
      OK
      to save the interface configuration.
    8. Repeat this procedure on another unused Ethernet interface to configure the other Network Packet Broker forwarding interface.
  2. Configure a Packet Broker profile to control how to forward the traffic to the layer 1 Transparent Bridge security chain.
    1. Select
      Objects
      Packet Broker Profile
      and
      Add
      a new profile or modify an existing profile.
    2. Give the profile a
      Name
      and
      Description
      so that you easily identify its purpose.
    3. On the
      General
      tab:
      • Select
        Transparent Bridge (Layer 1)
        as the
        Security Chain Type
        .
      • Enable IPv6
        if the traffic is IPv6 traffic.
      • Select the
        Flow Direction
        .
        Your network topology determines whether to use unidirectional or bidirectional flows. The performance is approximately the same using either method.
        To use one firewall interface to forward both the c2s and s2c session flows to the security chain and use the other firewall interface to receive both session flows back from the security chain, select
        Unidirectional
        .
        To use
        Interface #1
        to forward the c2s flow to the security chain and receive the s2c flow from the security chain, and use
        Interface #2
        to forward the s2c flow to the security chain and receive the c2s flow from the security chain, select
        Bidirectional
        .
      • Specify the Network Packet Broker forwarding interface pair in
        Interface #1
        and
        Interface #2
        . Both interfaces must already be enabled for Network Packet Broker (see Prepare to Deploy Network Packet Broker) to be available for use. Be careful to pay attention to the directionality of flow when you configure which interface is
        Interface #1
        and which interface is
        Interface #2
        .
    4. The
      Security Chains
      tab is not used for Transparent Bridges.
    5. On the
      Health Monitor
      tab:
      • Select the type or types of health monitoring you want to perform so that you can control what happens if the security chain experiences a failure. You can select one, two, or all from
        Path Monitoring
        ,
        HTTP Monitoring
        , and
        HTTP Monitoring Latency
        .
        Path Monitoring
        —Checks device connectivity using pings.
        HTTP Monitoring
        —Checks device availability and response time.
        HTTP Monitoring Latency
        —Checks device processing speed and efficiency. When you select this option,
        HTTP Monitoring
        is automatically enabled as well.
      • Enabling one or more types of health monitoring activates the
        On Health Check Failure
        options, which determine how the firewall handles security chain traffic if there is a security chain health failure. The options are
        Bypass Security Chain
        and
        Block Session
        .
        Bypass Security Chain
        —The firewall forwards the traffic to its destination instead of to the security chain and the applies any configured Security profiles and protections to the traffic.
        Block Session
        —The firewall blocks the session.
        The method you select depends on how you want to treat the traffic if you can’t run the traffic through the security chain.
      • If you select more than one health check option, select whether you want the firewall to consider the health check as failed (
        Health Check Failed Condition
        ) if any one of the monitoring options records a failed condition (
        OR Condition
        ) or only if all of the selected monitoring options record a failed condition (
        AND Condition
        ). For example, if you enable all three health check options and one of the options records a failed condition, if you selected
        OR Condition
        , the firewall considers the security chain connection to be failed and executes the action you specified in
        On Health Check Failure
        . If you selected
        AND Condition
        , the firewall would still consider the connection to be healthy because two of the health metrics are still OK.
    6. Click
      OK
      to save the profile.
  3. Configure a Packet Broker policy to define the traffic to forward to the layer 1 Transparent Bridge security chain.
    1. Select
      Policies
      Network Packet Broker
      and
      Add
      a new policy rule or modify an existing policy rule.
    2. On the
      General
      tab, give the policy rule a
      Name
      and
      Description
      so that you easily identify its purpose, add an
      Audit Comment
      , and apply tags if you use them.
    3. On the
      Source
      tab, identify the source zones, IP addresses, users, and devices of the traffic that you want the rule to forward to the security chain.
    4. On the
      Destination
      tab, identify the destination zones, IP addresses, and devices of the traffic that you want the rule to forward to the security chain.
    5. On the
      Application/Service/Traffic
      tab, identify the applications and services you want the rule to forward to the security chain. Unless the rule control applications that you expect to use non-standard ports such as internal custom applications, the best practice is to set the
      Service
      to
      Application Default
      so that applications that exhibit evasive behavior by using non-standard ports are blocked.
      For the
      Traffic Type
      , select all of the types of traffic that you want the rule to forward to the security chain.
      Forward TLS(Decrypted) Traffic
      is the default selection. You can select any combination of
      Forward TLS(Decrypted) Traffic
      ,
      Forward TLS(Non-Decrypted)
      , and
      Forward Non-TLS Traffic
      to forward to the security chain.
    6. On the
      Path Selection
      tab, select the Packet Broker profile you created in Step 2 or create a new profile to control how to send the traffic that the policy rule controls to the security chain.
  4. Repeat Step 1 through Step 3 to create more layer 1 Transparent Bridge security chains.
    For each layer 1 Transparent Bridge security chain:
    • The two Ethernet interfaces used as Network Packet Broker forwarding interfaces must be dedicated to each security chain. Ethernet interfaces used for a Transparent Bridge security chain cannot be used for any other purpose or carry any other traffic.
    • Each pair of Network Packet Broker forwarding interfaces connects to one layer 1 Transparent Bridge security chain.
    You can load balance traffic by creating Network Packet Broker policy rules that divide traffic relatively equally among the Transparent Bridge security chains. You can also use policy rules to direct specific traffic and types of traffic through specific security chains.
    Layer 1 Transparent Bridge security chains cannot failover to another security chain because they are not routed. Use the
    Health Monitor
    tab in the Packet Broker profile to configure how to handle traffic if a Transparent Bridge security chain fails.

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