Configure a Loopback Interface
Let us learn to configure a loopback interface.
Loopback is a logical, virtual interface used
to emulate a WAN port to provide LAN functionality. You can free
up a physical port previously used for LAN/WAN configuration by
designating a loopback interface. You can configure a maximum of
four loopback interfaces per device.
ION devices on
versions
4.5.3 or later
at a site, support loopback interface. A loopback
interface can only be used as a WAN port on interfaces with no hardware
bypass circuitry. Interfaces with no hardware bypass circuitry per
device are as follows:- ION 1000—All ports.
- ION 1200—All ports.
- ION 2000—Ports 1–3.
- ION 7000—Ports 1–4, 9–14.
- Virtual IONs—All non-controller ports.
A loopback
interface may be brought up or down administratively and may not contain
any sub-interfaces or IP configurations.
- You can update or delete a loopback interface. However, you cannot delete if it is part of a bypass pair.
- Decouple a port coupled with another port before a loopback interface can be coupled to create a bypass pair.
- The only valid option in the Use These Ports For drop-down is Private Layer 2 for a bypass pair that is made up of a physical LAN port and a loopback interface as the WAN port.
- The network policy rules assigned to such a site must not have any rules using the Direct on private WAN path. Valid paths are Direct on public or VPN on public. Traffic is dropped if a direct on private path is used.
- From select a device and clickConfigure the device.
- Select theInterfacestab.
- On the interface configuration page for a device, click the+add icon to add a loopback interface and selectAdd.
- ForAdmin Up, selectNoorYesto administratively bring the interface up or down.
- Enter aDescriptionand selectCreate Loopback.The system assigns a default loopback ID to the interface. A confirmation message displays that the loopback interface is successfully created.
- Next, select a port to be configured with a loopback interface.
- ForAdmin Up, selectNoorYesto administratively bring the interface up or down. The default is Yes.
- (Optional)Enter aDescription.
- From theInterface Typedrop-down, selectBypass Pair.
- From thePair Withdrop-down, select the Loopback Interface.A confirmation message displays.
- SelectDoneto create a bypass pair with the loopback interface successfully.A confirmation message displays the port's successful creation and the loopback interface.
- ForUse These Ports For, selectPrivate L2from the drop-down.This is the only valid option for a bypass pair that is made of a physical LAN port and a loopback interface for the WAN port.
- Select theCircuit Labelfrom the drop-down.
- (Optional)If you chooseCopy Settings from Another Port, select the bypass pair to copy the settings. If not, you may leave it blank.
- Similar to configuring bypass pairs, forAttached Networks, enter aVLAN ID,IP Address at Router, optionalNetwork Context, and toggle the scope tpLocalorGlobalscope.
- Save Bypass Pair.The port and the loopback interface are displayed under Interfaces.
