Cisco 500 Series, Configuration Manual

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Cisco Security Appliance Command Line Configuration Guide
OL-12172-03
Chapter 4 Configuring Switch Ports and VLAN Interfaces for the Cisco ASA 5505 Adaptive Security Appliance
Configuring a Switch Port as a Trunk Port
hostname(config-if)# switchport access vlan 400
hostname(config-if)# no shutdown
hostname(config-if)# interface ethernet 0/4
hostname(config-if)# switchport access vlan 500
hostname(config-if)# no shutdown
Configuring a Switch Port as a Trunk Port
By default, all switch ports are shut down. This procedure tells how to create a trunk port that can carry
multiple VLANs using 802.1Q tagging. Trunk mode is available only with the Security Plus license.
To create an access port, where an interface is assigned to only one VLAN, see the “Configuring Switch
Ports as Access Ports” section on page 4-9 .
By default, the speed and duplex for switch ports are set to auto-negotiate. The default auto-negotiation
setting also includes the Auto-MDI/MDIX feature. Auto-MDI/MDIX eliminates the need for crossover
cabling by performing an internal crossover when a straight cable is detected during the auto-negotiation
phase. Either the speed or duplex must be set to auto-negotiate to enable Auto-MDI/MDIX for the
interface. If you explicitly set both the speed and duplex to a fixed value, thus disabling auto-negotiation
for both settings, then Auto-MDI/MDIX is also disabled.
To configure a trunk port, perform the following steps:
Step 1 To specify the switch port you want to configure, enter the following command:
hostname(config)# interface ethernet0/ port
Where port is 0 through 7. For example, enter the following command:
hostname(config)#
interface ethernet0/1
Step 2 To assign VLANs to this trunk, enter the following command:
hostname(config-if)# switchport trunk allowed vlan vlan_range
where the vlan_range (with VLANs between 1 and 4090) can be identified in one of the following ways:
• A single number (n)
•
A range (n-x)
Separate numbers and ranges by commas, for example:
5,7-10,13,45-100
You can enter spaces instead of commas, but the command is saved to the configuration with commas.
This switch port cannot pass traffic until you assign at least one VLAN to it. Trunk ports do not support
untagged packets; there is no native VLAN support, and the adaptive security appliance drops all packets
that do not contain a tag specified in this command.
Step 3 To make this switch port a trunk port, enter the following command:
hostname(config-if)# switchport mode trunk
To restore this port to access mode, enter the switchport mode access command.
Step 4 (Optional) To prevent the switch port from communicating with other protected switch ports on the same
VLAN, enter the following command:
hostname(config-if)# switchport protected