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Assigning an IP Address to a VLAN
VLANs are a Layer 2 feature. For two physical interfaces on different VLANs to communicate, assign an IP address to the
VLANs to route traffic between the two interfaces.
The shutdown command in INTERFACE mode does not affect Layer 2 traffic on the interface; the shutdown command only
prevents Layer 3 traffic from traversing over the interface.
NOTE: You cannot assign an IP address to the Default VLAN (VLAN 1). To assign another VLAN ID to the Default VLAN,
use the default vlan-id vlan-id command.
In Dell Networking OS, you can place VLANs and other logical interfaces in Layer 3 mode to receive and send routed traffic. For
more information, refer to Bulk Configuration.
To assign an IP address, use the following command.
● Configure an IP address and mask on the interface.
INTERFACE mode
ip address ip-address mask [secondary]
○ ip-address mask — Enter an address in dotted-decimal format (A.B.C.D) and the mask must be in slash format
(/24).
○ secondary — This is the interface’s backup IP address. You can configure up to eight secondary IP addresses.
Enabling 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. Dell Networking OS has a Null VLAN to eliminate this vulnerability. When
you enable the Null VLAN, all ports are placed into it by default, so 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.
To enable Null VLAN, use the following command.
● Disable the default VLAN, so that all ports belong to the Null VLAN until configured as a member of another VLAN.
CONFIGURATION mode
default-vlan disable
Default: the default VLAN is enabled (no default-vlan disable).
Configuring Native VLANs
Traditionally, ports can be either untagged for membership to one VLAN or tagged for membership to multiple VLANs.
You must connect an untagged port to a VLAN-unaware station (one that does not understand VLAN tags) and connect a
tagged port to a VLAN-aware station (one that generates and understands VLAN tags).
Native VLAN support breaks this barrier so that you can connect a port to both VLAN-aware and VLAN-unaware stations. Such
ports are referred to as hybrid ports. Physical and port-channel interfaces may be hybrid ports.
Native VLAN is useful in deployments where a Layer 2 port can receive both tagged and untagged traffic on the same physical
port. The classic example is connecting a voice-over-IP (VoIP) phone and a PC to the same port of the switch. The VoIP phone
is configured to generate tagged packets (with VLAN = VOICE VLAN) and the attached PC generates untagged packets.
NOTE:
You cannot configure an existing switchport or port channel interface for Native VLAN. Interfaces must have no
other Layer 2 or Layer 3 configurations when using the portmode hybrid command or a similar message displays: %
Error: Port is in Layer-2 mode Gi 5/6.
To configure a port so that it can be a member of untagged and tagged VLANs, use the following commands.
1. Remove any Layer 2 or Layer 3 configurations from the interface.
INTERFACE mode
Virtual LANs (VLANs)
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