The loopback interface on the VPN Gateway is implemented as a virtual network interface providing the ability to anchor services running on the VPN Gateway to a single host address. The interface is defined through the AT&T Administration Server.

The loopback interface has the ability to be configured as Internet Only, VPN Only or a VPN Enabled interface. Any loopback interfaces that are defined with VPN capabilities will be announced through the appropriate VPN tunnel network advertisement. In a multiple tunnel scenario, VPN enabled loopback interfaces can be associated with a specific VPN tunnel(s).

The AT&T Administration Server provides the ability to configure the following services on the VPN Gateway to take advantage of the loopback interface address: SNMP Traps/Informs, SNMP Polling, NetFlow, and Remote Syslog.