Default Settings For Switchport Blocking; Configuring Switchport Blocking - Cisco Nexus 9000 Series Configuration Manual

Default Settings for Switchport Blocking

• Switchport blocking is supported on all switched ports (including PVLAN ports) and is applied to all
• Switchport blocking is not supported for FEX ports.
• When you block unknown multicast or unicast traffic for a port channel, it is blocked on all ports in the
• Switchport blocking does not offer levels of control. It prevents the flooding of all unknown egress
• Switchport blocking drops control packets that originate from the CPU on Cisco Nexus 9500 Series
Default Settings for Switchport Blocking
This table lists the default settings for switchport blocking parameters.
Table 39: Default Switchport Blocking Parameters
Parameters
Switchport blocking

Configuring Switchport Blocking

By default, the switch floods packets with unknown destination MAC addresses to all ports. To prevent the
forwarding of such traffic, you can configure a port to block unknown multicast or unicast packets.
SUMMARY STEPS
1. configure terminal
2. interface {ethernet slot/port | port-channel number}
3. [no] switchport block {multicast | unicast}
4. (Optional) show interface [ethernet slot/port | port-channel number] switchport
5. (Optional) copy running-config startup-config
DETAILED STEPS
Command or Action
Step 1
configure terminal
Example:
switch# configure terminal
switch(config)#
Step 2 interface {ethernet slot/port | port-channel number}
Example:
Cisco Nexus 9000 Series NX-OS Security Configuration Guide, Release 9.x
450
VLANs on which the port is forwarding.
port-channel group.
multicast or unicast packets on the specified port.
switches. It does not drop packets on Cisco Nexus 9300 Series switches.
Default
Disabled
Purpose
Enters global configuration mode.
Enters interface configuration mode.
Configuring Switchport Blocking