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Configuring Unknown Unicast Forwarding (CLI Procedure)

Note: This task uses Junos OS for EX Series switches or QFX Series with support for the Enhanced Layer 2 Software (ELS) configuration style. If your EX Series switch runs software that does not support ELS, see Configuring Unknown Unicast Forwarding (CLI Procedure). For ELS details, see Getting Started with Enhanced Layer 2 Software

Unknown unicast traffic consists of packets with unknown destination MAC addresses. By default, the switch floods these packets to all interfaces associated with a VLAN. Forwarding such traffic to interfaces on the switch can create a security issue.

To prevent flooding unknown unicast traffic across the switch, configure unknown unicast forwarding to direct all unknown unicast packets within a VLAN out to a specific interface. You can configure each VLAN to divert unknown unicast traffic to different interfaces or use one interface for multiple VLANs.

To configure unknown unicast forwarding options:

  • Configure unknown unicast forwarding for a specific VLAN (here, the VLAN name is employee), and specify the interface to which all unknown unicast traffic will be forwarded:
    [edit switch-options]
    user@switch# set unknown-unicast-forwarding vlan vlan-name interface ge-x/y/z.0
 

Related Documentation

 

Published: 2014-07-23

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