Reference Guide

844 | Virtual LANs (VLAN)
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Enable Null VLAN as the Default VLAN
In a Carrier Ethernet for Metro Service environment, service providers who perform frequent
reconfigurations for customers with changing requirements occasionally enable multiple interfaces, each
connected to a different customer, before the interfaces are fully configured. This presents a vulnerability
because both interfaces are initially placed in the native VLAN, VLAN 1, and for that period customers are
able to access each other's networks. FTOS has a Null VLAN to eliminate this vulnerability. When you
enable the Null VLAN, all ports are placed into by it default, so that even if you activate the physical ports
of multiple customers, no traffic is allowed to traverse the links until each port is place in another VLAN.
Task Command Syntax Command Mode
Disable the default VLAN, so that all ports belong to
the Null VLAN until configured as a member of another
VLAN.
default-vlan disable
Default: the default VLAN is enabled
(
no default-vlan disable).
CONFIGURATION