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Configuring Port Mirroring on Logical Interfaces

Layer 2 Port Mirroring Firewall Filters

This topic describes the following information:

Layer 2 Port Mirroring Firewall Filters Overview

On an MX Series router and on an EX Series switch, you can configure a firewall filter term to specify that Layer 2 port mirroring is to be applied to all packets at the interface to which the firewall filter is applied.

You can apply a Layer 2 port-mirroring firewall filter to the input or output logical interfaces (including aggregated Ethernet logical interfaces), to traffic forwarded or flooded to a VLAN, or traffic forwarded or flooded to a VPLS routing instance.

MX Series routers and EX Series switches support Layer 2 port mirroring of VPLS (family ethernet-switching or family vpls) traffic and Layer 2 VPN traffic with family ccc in a Layer 2 environment

Within a firewall filter term, you can specify the Layer 2 port-mirroring properties under the then statement in either of the following ways:

  • Implicitly reference the Layer 2 port mirroring properties in effect on the port.

  • Explicitly reference a particular named instance of Layer 2 port mirroring.

Note:

When configuring a Layer 2 port-mirroring firewall filter, do not include the optional from statement that specifies match conditions based on the route source address. Omit this statement so that all packets are considered to match and all actions and action-modifiers specified in the then statement are taken.

If you want to mirror all incoming packets, then you must not use the from statement; /* comment: one configure filter terms with from if they are interested in mirroring only a subset of packets.

Note:

If you associate integrated routing and bridging (IRB) with the VLAN (or VPLS routing instance), and also configure within the VLAN (or VPLS routing instance) a forwarding table filter with the port-mirror or port-mirror-instance action, then the IRB packet is mirrored as a Layer 2 packet. You can disable this behavior by configuring the no-irb-layer-2-copy statement in the VLAN (or VPLS routing instance).

For a detailed description of how to configure a Layer 2 port-mirroring firewall filter, see Defining a Layer 2 Port-Mirroring Firewall Filter.

For detailed information about how you can use Layer 2 port-mirroring firewall filters with MX Routers and EX Series switches configured as provider edge (PE) routers or PE switches, see Understanding Layer 2 Port Mirroring of PE Router Logical Interfaces. For detailed information about configuring firewall filters in general (including in a Layer 3 environment), see the Routing Policies, Firewall Filters, and Traffic Policers User Guide.

Mirroring of Packets Received or Sent on a Logical Interface

To mirror Layer 2 traffic received or sent on a logical interface, apply a port-mirroring firewall filter to the input or output of the interface.

A port-mirroring firewall filter can also be applied to an aggregated-Ethernet logical interface. For details, see Understanding Layer 2 Port Mirroring of PE Router Aggregated Ethernet Interfaces.

Note:

If port-mirroring firewall filters are applied at both the input and output of a logical interface, two copies of each packet are mirrored. To prevent the router or switch from forwarding duplicate packets to the same destination, you can enable the “mirror-once” option for Layer 2 port mirroring in the global instance for the Layer 2 packet address family.

Mirroring of Packets Forwarded or Flooded to a VLAN

To mirror Layer 2 traffic forwarded to or flooded to a VLAN, apply a port-mirroring firewall filter to the input to the forwarding table or flood table. Any packet received for the VLAN forwarding or flood table and that matches the filter conditions is mirrored.

For more information about VLANs, see Understanding Layer 2 Bridge Domains . For information about flooding behavior in a VLAN, see Understanding Layer 2 Learning and Forwarding for Bridge Domains .

Note:

When you configure port mirroring on any interface under one VLAN, the mirrored packet can move to an external analyzer located on different VLANs.

Mirroring of Packets Forwarded or Flooded to a VPLS Routing Instance

To mirror Layer 2 traffic forwarded to or flooded to a VPLS routing instance, apply a port-mirroring firewall filter to the input to the forwarding table or flood table. Any packet received for the VPLS routing instance forwarding or flood table and that matches the filter condition is mirrored.

For more information about VPLS routing instances, see Configuring a VPLS Routing Instance and Configuring VLAN Identifiers for Bridge Domains and VPLS Routing Instances. For information about flooding behavior in VPLS, see the Junos OS VPNs Library for Routing Devices.

Defining a Layer 2 Port-Mirroring Firewall Filter

For virtual private LAN service (VPLS) traffic (family ethernet-switching or family vpls) and for Layer 2 VPNs with family cccon MX Series routers and on EX Series switches only, you can define a firewall filter that specifies Layer 2 port mirroring as the action to be performed if a packet matches the conditions configured in the firewall filter term.

You can use a Layer 2 port-mirroring firewall filter in the following ways:

  • To mirror packets received or sent on a logical interface.

  • To mirror packets forwarded or flooded to a VLAN.

  • To mirror packets forwarded or flooded to a VPLS routing instance.

  • To mirror tunnel interface input packets only to multiple destinations.

For a summary of the three types of Layer 2 port-mirroring you can configure on an MX Series router and on an EX Series switch, see Application of Layer 2 Port Mirroring Types.

To define a firewall filter with a Layer 2 port-mirroring action:

  1. Enable configuration of firewall filters for Layer 2 packets that are part of a VLAN, a Layer 2 switching cross-connect, or a virtual private LAN service (VPLS):

    The value of the family option can be ethernet-switching , ccc, or vpls.

  2. Enable configuration of a firewall filter pm-filter-name:
  3. Enable configuration of a firewall filter term pm-filter-term-name:
  4. (Optional) Specify the firewall filter match conditions based on the route source address only if you want to mirror a subset of the sampled packets.
    Note:

    If you want all sampled packets to be considered to match (and be subjected to the actions specified in the then statement), then omit the from statement altogether.

  5. Enable configuration of the action and action-modifier to apply to matching packets:
  6. Specify the actions to be taken on matching packets:

    The recommended value for the action is accept. If you do not specify an action, or if you omit the then statement entirely, all packets that match the conditions in the from statement are accepted.

  7. Specify Layer 2 port mirroring or a next-hop group as the action-modifier:
    • To reference the Layer 2 port mirroring properties currently in effect for the Packet Forwarding Engine or PIC associated with the underlying physical interface, use the port-mirror statement:

    • To reference the Layer 2 port mirroring properties configured in a specific named instance, use the port-mirror-instance pm-instance-name action modifier:

      If the underlying physical interface is not bound to a named instance of Layer 2 port mirroring but instead is implicitly bound to the global instance of Layer 2 port mirroring, then traffic at the logical interface is mirrored according to the properties specified in the named instance referenced by the port-mirror-instance action modifier.

    • To reference a next-hop group that specifies the next-hop addresses (for sending additional copies of packets to an analyzer), use the next-hop-group pm-next-hop-group-name action modifier:

      For configuration information about next-hop groups, see Defining a Next-Hop Group for Layer 2 Port Mirroring. If you specify a next-hop group for Layer 2 port mirroring, the firewall filter term applies to the tunnel interface input only.

  8. Verify the minimum configuration of the Layer 2 port-mirroring firewall filter:

    In the firewall filter term then statement, the action-modifier can be port-mirror, port-mirror-instance , or next-hop-group pm-next-hop-group-name.

Configuring Protocol-Independent Firewall Filter for Port Mirroring

On MX Series routers with MPCs, you can configure a firewall filter to mirror Layer 2 and Layer 3 packets at a global level and at an instance level. When port mirror is configured at ingress or egress, the packet entering or exiting an interface is copied and the copies are sent to the local interface for local monitoring.

Note:

Starting with Junos OS Release 13.3R6, only MPC interfaces support family any to do port mirroring. DPC interfaces do not support family any.

Typically, the firewall filter is configured such that it mirrors either Layer 2 or Layer 3 packets based on the family configured at the interface. However, in case of an integrated routing and bridging (IRB) interface, Layer 2 packets are not completely mirrored because IRB interfaces are configured to mirror only Layer 3 packets. On such an interface, you can configure a firewall filter and port mirroring parameters in the family any to ensure that a packet is completely mirrored irrespective of whether it is a Layer 2 or a Layer 3 packet.

Note:
  • For port mirroring at an instance, you can configure one or more families such as inet, inet6, ccc, and vpls simultaneously for the same instance.

  • In case of Layer 2 port mirroring, VLAN tags, MPLS headers are retained and can be seen in the mirrored copy at egress.

  • For VLAN normalization, the information before normalization is seen for a mirrored packet at ingress. Similarly, at egress, the information after normalization is seen for the mirrored packet.

Before you begin configuring port mirroring, you must configure valid physical interfaces.

To configure a protocol-independent firewall filter for port mirroring:

  1. Configure a global firewall filter for mirroring egress or ingress traffic.
  2. Configure a firewall filter to mirror traffic for an instance.
  3. Configure mirroring parameters for egress and ingress traffic.
  4. Configure mirroring parameters for an instance. In this configuration, you can specify the output or destination for the Layer 2 packets to be either a valid next-hop group or a Layer 2 interface.
  5. Configure the firewall filter at the ingress or egress interface on which the packets are transmitted.

Example: Mirroring Employee Web Traffic with a Firewall Filter

Requirements

This example uses the following hardware and software components:

  • One switch

  • Junos 14.1X53-D20

Overview

In this example, xe-0/0/0 and xe-0/0/6 serve as connections for employee computers. Interface xe-0/0/47 is connected to a device running an analyzer application.

Rather than mirror all traffic, it is usually desirable to mirror only certain traffic. This is a more-efficient use of your bandwidth and hardware and might be necessary because of constraints on these assets. This example mirrors only traffic sent from employee computers to the Web.

Topology

Figure 1 shows the network topology for this example.

Figure 1: Network Topology for Local Port Mirroring ExampleNetwork Topology for Local Port Mirroring Example

Configuring

To specify that the only traffic that will be mirrored is traffic sent by employees to the Web, perform the tasks explained in this section. To select this traffic for mirroring, you use a firewall filter to specify this traffic and direct it to a port-mirroring instance.

Procedure

CLI Quick Configuration

To quickly configure local port mirroring of traffic from employee computers that is destined for the Web, copy the following commands and paste them into a switch terminal window:

Step-by-Step Procedure

To configure local port mirroring of employee to web traffic from the two ports connected to employee computers:

  1. Configure a port-mirroring instance, including the output interface and the IP address of the device running the analyzer application as the next hop. (Configure only the output—the input comes from the filter.) You must also specifying that the mirror is for IPv4 traffic (family inet).

  2. Configure an IPv4 (family inet) firewall filter called watch-employee that includes a term to match traffic sent to the Web and send it to the port-mirroring instance. Traffic sent to and arriving from the corporate subnet (destination or source address of 192.0.nn.nn/24) does not need to be copied, so first create another term to accept that traffic before it reaches the term that sends Web traffic to the instance:

  3. Configure addresses for the IPv4 interfaces connected to the employee computers and the analyzer device:

  4. Apply the firewall filter to the appropriate interfaces as an ingress filter:

Results

Check the results of the configuration:

Verification

Verifying That the Analyzer Has Been Correctly Created

Purpose

Verify that the analyzer has been created on the switch with the appropriate input interfaces and appropriate output interface.

Action

You can verify that the port mirror analyzer has been configured as expected using the show forwarding-options port-mirroring command.

Meaning

This output shows that the port-mirroring instance has a ratio of 1 (mirroring every packet, the default setting) and the maximum size of the original packet that was mirrored (0 indicates the entire packet). If the state of the output interface is down or if the output interface is not configured, the value of state will be down and the instance will not be programmed for mirroring.

Layer 2 Port Mirroring of PE Router or PE Switch Logical Interfaces

For a router or switch configured as a provider edge (PE) device on the customer-facing edge of a service provider network, you can apply a Layer 2 port-mirroring firewall filter at the following ingress and egress points to mirror the traffic between the router or switch and customer edge (CE) devices, which are typically also routers and Ethernet switches.

Table 1 describes the ways in which you can apply Layer 2 port-mirroring firewall filters to a router or switch configured as a PE device.

Table 1: Application of Layer 2 Port Mirroring Firewall Filters on PE Devices

Point of Application

Scope of Mirroring

Notes

Configuration Details

Ingress Customer-Facing Logical Interface

Packets originating within a service provider customer’s network, sent first to a CE device, and sent next to the PE device.

You can also configure aggregated Ethernet interfaces between CE devices and PE devices for VPLS routing instances. Traffic is load-balanced across all of the links in the aggregated interface.

Traffic received on an aggregated Ethernet interface is forwarded over a different interface based on a lookup of the destination MAC (DMAC) address:

  • Packets destined for a local site are sent out of the load-balanced child interface.

  • Packets destined for the remote site are encapsulated and forwarded over a label-switched path (LSP).

See Applying Layer 2 Port Mirroring to a Logical Interface.

For more information about VPLS routing instances, see Configuring a VPLS Routing Instance and Configuring VLAN Identifiers for Bridge Domains and VPLS Routing Instances.

Egress Customer-Facing Logical Interface

Unicast packets being forwarded by the PE device to another PE device.

NOTE: If you apply a port-mirroring filter to the output for a logical interface, only unicast packets are mirrored. To mirror multicast, unknown unicast, and broadcast packets, apply a filter to the input to the flood table of a VLAN or VPLS routing instance.

See Applying Layer 2 Port Mirroring to a Logical Interface.

Input to a VLAN Forwarding Table or Flood Table

Forwarding traffic or flood traffic sent to the VLAN from a CE device.

Forwarding and flood traffic typically consists of broadcast packets, multicast packets, unicast packets with an unknown destination MAC address, or packets with a MAC entry in the DMAC routing table.

See Applying Layer 2 Port Mirroring to Traffic Forwarded or Flooded to a Bridge Domain. For information about flooding behavior in VPLS, see the Junos OS VPNs Library for Routing Devices.

Input to a VPLS Routing Instance Forwarding Table or Flood Table

Forwarding traffic or flood traffic sent to the VPLS routing instance from a CE device.

See Applying Layer 2 Port Mirroring to Traffic Forwarded or Flooded to a VPLS Routing Instance. For information about flooding behavior in VPLS, see the Junos OS VPNs Library for Routing Devices.

Layer 2 Port Mirroring of PE Router or PE Switch Aggregated Ethernet Interfaces

An aggregated Ethernet interface is a virtual aggregated link that consists of a set of physical interfaces of the same speed and operating in full-duplex link connection mode. You can configure aggregated Ethernet interfaces between CE devices and PE devices for VPLS routing instances. Traffic is load-balanced across all of the links in the aggregated interface. If one or more links in the aggregated interface fails, the traffic is switched to the remaining links.

You can apply a Layer 2 port-mirroring firewall filter to an aggregated Ethernet interface to configure port mirroring at the parent interface. However, if any child interfaces are bound to different Layer 2 port-mirroring instances, packets received at the child interfaces will be mirrored to the destinations specified by their respective port-mirroring instances. Thus, multiple child interfaces can mirror packets to multiple destinations.

For example, suppose the parent aggregated Ethernet interface instance ae0 has two child interfaces:

  • xe-2/0/0

  • xe-3/1/2

Suppose that these child interfaces on ae0 are bound to two different Layer 2 port-mirroring instances:

  • pm_instance_A—A named instance of Layer 2 port-mirroring, bound to child interface xe-2/0/0.

  • pm_instance_B—A named instance of Layer 2 port-mirroring, bound to child interface xe-3/1/2.

Now suppose you apply a Layer 2 port-mirroring firewall filter to the Layer 2 traffic sent on ae0.0 (logical unit 0 on the aggregated Ethernet interface instance 0). This enables port mirroring on ae0.0, which has the following effect on the processing of traffic received on the child interfaces for which Layer 2 port-mirroring properties are specified:

  • The packets received on xe-2/0/0 are mirrored to the output interfaces configured in port-mirroring instance pm_instance_A.

  • The packets received on xe-3/1/2.0 are mirrored to the output interfaces configured in port-mirroring instance pm_instance_B.

Because pm_instance_A and pm_instance_B can specify different packet-selection properties or mirror destination properties, the packets received on xe-2/0/0 and xe-3/1/2.0 can mirror different packets to different destinations.

Applying Layer 2 Port Mirroring to a Logical Interface

You can apply a Layer 2 port-mirroring firewall filter to the input or to the output of a logical interface, including an aggregated Ethernet logical interface. Only packets of the address-type family specified by the filter action are mirrored.

Before you begin, complete the following task:

  • Define a Layer 2 port-mirroring firewall filter to be applied to the input to a logical interface or output to a logical interface. For details, see Defining a Layer 2 Port-Mirroring Firewall Filter.

    Note:

    This configuration task shows two Layer 2 port-mirroring firewall filters: one filter applied to the logical interface ingress traffic, and one filter applied to the logical interface egress traffic.

To apply a Layer 2 port-mirroring firewall filter to an input or output logical interface:

  1. Configure the underlying physical interface for the logical interface.

    1. Enable configuration of the underlying physical interface:

      Note:

      A port-mirroring firewall filter can also be applied to an aggregated-Ethernet logical interface.


    2. For Fast Ethernet and Gigabit Ethernet interfaces and aggregated Ethernet interfaces configured for VPLS, enable the reception and transmission of 802.1Q VLAN-tagged frames on the interface:


    3. For Ethernet interfaces that have IEEE 802.1Q VLAN tagging and bridging enabled and that must accept packets carrying TPID 0x8100 or a user-defined TPID, set the logical link-layer encapsulation type:

  2. Configure the logical interface to which you want to apply a Layer 2 port-mirroring firewall filter.

    1. Specify the logical unit number:


    2. For a Fast Ethernet, Gigabit Ethernet, or Aggregated Ethernet interface, bind an 802.1Q VLAN tag ID to the logical interface:

  3. Enable specification of an input or output filter to be applied to Layer 2 packets that are part of bridging domain, Layer 2 switching cross-connects, or virtual private LAN service (VPLS).
    • If the filter is to be evaluated when packets are received on the interface:

    • If the filter is to be evaluated when packets are sent on the interface:

    The value of the family option can be ethernet-switching, ccc, or vpls.

    Note:

    If port-mirroring firewall filters are applied at both the input and output of a logical interface, two copies of each packet are mirrored. To prevent the router or switch from forwarding duplicate packets to the same destination, include the optional mirror-once statement at the [edit forwarding-options] hierarchy level.

  4. Verify the minimum configuration for applying a named Layer 2 port mirroring firewall filter to a logical interface:

Applying Layer 2 Port Mirroring to Traffic Forwarded or Flooded to a Bridge Domain

You can apply a Layer 2 port-mirroring firewall filter to traffic being forwarded or flooded to a bridge domain. Only packets of the specified family type and forwarded or flooded to that bridge domain are mirrored.

Before you begin, complete the following task:

  • Define a Layer 2 port-mirroring firewall filter to be applied to the traffic being forwarded to a bridge domain or flooded to a bridge domain. For details, see Defining a Layer 2 Port-Mirroring Firewall Filter.

    Note:

    This configuration task shows two Layer_2 port-mirroring firewall filters: one filter applied to the bridge domain forwarding table ingress traffic, and one filter applied to the bridge domain flood table ingress traffic.

To apply a Layer 2 port-mirroring firewall filter to the forwarding table or flood table of a bridge domain:

  1. Enable configuration of the bridge domain bridge-domain-name to which you want to apply a Layer 2 port-mirroring firewall filter for forwarded or flooded traffic:
  2. Configure the bridge domain:
  3. Enable configuration of traffic forwarding on the bridge domain:
  4. Apply a Layer 2 port-mirroring firewall filter to the bridge domain forwarding table or flood table.
    • To mirror packets being forwarded to the bridge domain:

    • To mirror packets being flooded to the bridge domain:

  5. Verify the minimum configuration for applying a Layer 2 port-mirroring firewall filter to the forwarding table or flood table of the bridge domain.

    1. Navigate to the hierarchy level at which the bridge domain is configured:

      • [edit]

      • [edit routing-instances routing-instance-name]


    2. Display the bridge domain configurations:

Applying Layer 2 Port Mirroring to Traffic Forwarded or Flooded to a VPLS Routing Instance

You can apply a Layer 2 port-mirroring firewall filter to traffic being forwarded or flooded to a VPLS routing instance. Only packets of the specified family type and forwarded or flooded to that VPLS routing instance are mirrored.

Before you begin, complete the following task:

  • Define a Layer 2 port-mirroring firewall filter to be applied to the traffic being forwarded to a VPLS routing instance or flooded to a VLAN. For details, see Defining a Layer 2 Port-Mirroring Firewall Filter.

    Note:

    This configuration task shows two Layer_2 port-mirroring firewall filters: one filter applied to the VPLS routing instance forwarding table ingress traffic, and one filter applied to the VPLS routing instance flood table ingress traffic.

To apply a Layer 2 port-mirroring firewall filter to the forwarding table or flood table of a VPLS routing instance:

  1. Enable configuration of the VPLS routing instance to which you want to apply a Layer 2 port-mirroring firewall filter for forwarded or flooded traffic:

    For more detailed configuration information, see Configuring a VPLS Routing Instance.

  2. Enable configuration of traffic forwarding on the VPLS routing instance:
  3. Apply a Layer 2 port-mirroring firewall filter to the VPLS routing instance forwarding table or flood table.
    • To mirror packets being forwarded to the VPLS routing instance:

    • To mirror packets being flooded to the VPLS routing instance:

  4. Verify the minimum configuration for applying a Layer 2 port-mirroring firewall filter to the forwarding table or flood table of the VPLS routing instance:

Applying Layer 2 Port Mirroring to Traffic Forwarded or Flooded to a VLAN

You can apply a Layer 2 port-mirroring firewall filter to traffic being forwarded or flooded to a VLAN. Only packets of the specified family type and forwarded or flooded to that VLAN are mirrored.

Before you begin, complete the following task:

  • Define a Layer 2 port-mirroring firewall filter to be applied to the traffic being forwarded to a VLAN or flooded to a VLAN. For details, see Defining a Layer 2 Port-Mirroring Firewall Filter.

    Note:

    This configuration task shows two Layer_2 port-mirroring firewall filters: one filter applied to the VLAN forwarding table ingress traffic, and one filter applied to the VLAN flood table ingress traffic.

To apply a Layer 2 port-mirroring firewall filter to the forwarding table or flood table of a VLAN:

  1. Enable configuration of the VLAN bridge-domain-name to which you want to apply a Layer 2 port-mirroring firewall filter for forwarded or flooded traffic:
  2. Configure the VLAN:
  3. Enable configuration of traffic forwarding on the VLAN:
  4. Apply a Layer 2 port-mirroring firewall filter to the VLAN forwarding table or flood table.
    • To mirror packets being forwarded to the VLAN:

    • To mirror packets being flooded to the VLAN:

  5. Verify the minimum configuration for applying a Layer 2 port-mirroring firewall filter to the forwarding table or flood table of the VLAN.

    1. Navigate to the hierarchy level at which the VLAN is configured:

      • [edit]

      • [edit routing-instances routing-instance-name]


    2. Display the VLAN configurations:

Example: Layer 2 Port Mirroring at a Logical Interface

The following steps describe an example in which the global port-mirroring instance and a port-mirroring firewall filter are used to configure Layer 2 port mirroring for the input to a logical interface.

  1. Configure the VLAN example-bd-with-analyzer, which contains the external packet analyzer, and the VLAN example-bd-with-traffic, which contains the source and destination of the Layer 2 traffic being mirrored:

    Assume that logical interface ge-2/0/0.0 is associated with an external traffic analyzer that is to receive port-mirrored packets. Assume that logical interfaces ge-2/0/6.0 and ge-3/0/1.2 will be traffic input and output ports, respectively.

  2. Configure Layer 2 port-mirroring for the global instance, with the port-mirroring destination being the VLAN interface associated with the external analyzer (logical interface ge-2/0/0.0 on VLAN example-bd-with-analyzer). Be sure to enable the option that allows filters to be applied to this port-mirroring destination:

    The input statement at the [edit forwarding-options port-mirroring] hierarchy level specifies that sampling begins every tenth packet and that each of the first five packets selected are to be mirrored.

    The output statement at the [edit forwarding-options port-mirroring family ethernet-switching] hierarchy level specifies the output mirror interface for Layer 2 packets in a bridging environment:

    • Logical interface ge-2/0/0.0, which is associated with the external packet analyzer, is configured as the port-mirroring destination.

    • The optional no-filter-check statement allows filters to be configured on this destination interface.

  3. Configure the Layer 2 port-mirroring firewall filter example-bridge-pm-filter:

    When this firewall filter is applied to the input or output of a logical interface for traffic in a bridging environment, Layer 2 port mirroring is performed according to the input packet-sampling properties and mirror destination properties configured for the Layer 2 port mirroring global instance. Because this firewall filter is configured with the single, default filter action accept, all packets selected by the input properties (rate = 10 and run-length = 5) match this filter.

  4. Configure the logical interfaces:

    Packets received at logical interface ge-2/0/6.0 on VLAN example-bd-with-traffic are evaluated by the port-mirroring firewall filter example-bridge-pm-filter. The firewall filter acts on the input traffic according to the filter actions configured in the firewall filter itself plus the input packet-sampling properties and mirror destination properties configured in the global port-mirroring instance:

    • All packets received at ge-2/0/6.0 are forwarded to their (assumed) normal destination at logical interface ge-3/0/1.2.

    • For every ten input packets, copies of the first five packets in that selection are forwarded to the external analyzer at logical interface ge-0/0/0.0 in the other VLAN, example-bd-with-analyzer.

    If you configure the port-mirroring firewall filter example-bridge-pm-filter to take the discard action instead of the accept action, all original packets are discarded while copies of the packets selected using the global port-mirroring input properties are sent to the external analyzer.

Example: Layer 2 Port Mirroring for a Layer 2 VPN

The following example is not a complete configuration, but shows all the steps needed to configure port mirroring on an L2VPN using family ccc.

  1. Configure the VLAN port-mirror-bd, which contains the external packet analyzer:

  2. Configure the Layer 2 VPN CCC to connect logical interface ge-2/0/1.0 and logical interface ge-2/0/1.1:

  3. Configure Layer 2 port mirroring for the global instance, with the port-mirroring destination being the VLAN interface associated with the external analyzer (logical interface ge-2/2/9.0 on VLAN example-bd-with-analyzer):

  4. Define the Layer 2 port-mirroring firewall filter pm_filter_ccc for family ccc:

  5. Apply the port mirror instance to the chassis:

  6. Configure interface ge-2/2/9 for the VLANs, and configure interface ge-2/0/1 for port mirroring with the pm_filter_ccc firewall filter:

Release History Table
Release
Description
13.3R6
Starting with Junos OS Release 13.3R6, only MPC interfaces support family any to do port mirroring.