disable flooding ports

With this command you can further identify the type of packets for which to block flooding.

disable flooding [all_cast | broadcast | multicast | unicast] ports [port_list | all]


Disables Layer 2 egress flooding on one or more ports.

Syntax Description

all_cast Specifies disabling egress flooding for all packets on specified ports.
broadcast Specifies disabling egress flooding only for broadcast packets.
multicast Specifies disabling egress flooding only for multicast packets.
unicast Specifies disabling egress flooding only for unknown unicast packets.
port_list Specifies one or more ports or slots and ports.
all Specifies all ports on the switch.


Enabled for all packet types.

Usage Guidelines



If an application requests specific packets on a specific port, those packets are not affected by the disable flooding ports command.
You might want to disable egress flooding to do the following:
  • enhance security
  • enhance privacy
  • improve network performance

This is particularly useful when you are working on an edge device in the network. The practice of limiting flooded egress packets to selected interfaces is also known as upstream forwarding.



If you disable egress flooding with static MAC addresses, this can affect many protocols, such as IP and ARP.
The following guidelines apply to enabling and disabling egress flooding:
  • Disabling multicasting egress flooding does not affect those packets within an IGMP membership group at all; those packets are still forwarded out. If IGMP snooping is disabled, multicast packets are not flooded.
  • Egress flooding can be disabled on ports that are in a load-sharing group. In a load-sharing group, the ports in the group take on the egress flooding state of the master port; each member port of the load-sharing group has the same state as the master port.
  • On all platforms FDB learning takes place on ingress ports and is independent of egress flooding; either can be enabled or disabled independently.
  • Disabling unicast or all egress flooding to a port also stops packets with unknown MAC addresses to be flooded to that port.
  • Disabling broadcast or all egress flooding to a port also stops broadcast packets to be flooded to that port.

You can disable egress flooding for unicast, multicast, or broadcast MAC addresses, as well as for all packets on the ports of the switch. The default behavior is enabled egress flooding for all packet types.


The following example disables unicast flooding on ports 10-12::

# disable flooding unicast port 10-27


This command was first available in ExtremeXOS 11.2.

Platform Availability

This command is available on ExtremeSwitching X435, X440-G2, X450-G2, X460-G2, X465, X590, X620, X670-G2, X690, X695, X870, 5320, 5420, and 5520 series switches.