Loopback Interface; Ipv4 Management And Interfaces - Cisco 350 Series Administration Manual

IP Configuration

Loopback Interface

Loopback Interface

IPv4 Management and Interfaces

Cisco 350, 350X and 550X Series Managed Switches, Firmware Release 2.4, ver 0.4
Overview
The loopback interface is a virtual interface whose operational state is always up. If the IP
address that is configured on this virtual interface is used as the local address when
communicating with remote IP applications, the communication will not be aborted even if the
actual route to the remote application was changed.
The operational state of a loopback interface is always up. You define an IP address (either
IPv4 or IPv6) on it and use this IP address as the local IP address for IP communication with
remote IP applications. Communication remains intact as long as the remote applications can
be reached from any one of the switch's active (non-loopback) IP interfaces. On the other
hand, if the IP address of an IP interface is used in communicating with remote applications,
the communication will be terminated when the IP interface is down.
A loopback interface does not support bridging; it cannot be a member of any VLAN, and no
layer 2 protocol can be enabled on it.
The IPv6 link-local interface identifier is 1.
Configuring a Loopback Interface
To configure an IPv4 loopback interface, add a loopback interface in
To configure an IPv6 loopback interface, add a loopback interface in the
This section covers the following topics:
• IPv4 Interface
• IPv4 Static Routes
• IPv4 Forwarding Table
• RIPv2
• VRRP
• ARP
• ARP Proxy
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IPv4 Interface.
IPv6 Addresses.
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