Loopback interface can be used to run network services for the local machines. It would be better to go with Unix domain socket but the other part is it requires explicit support in the application. You can use it for dominant purposes, as like: making disk images either for testing something in an isolated environment or backups.

Loopback Interface and the service

1.      They are usually for services that you need and don’t want to be exposed to the network. It would assist privacy when you want to secure your network / server by encapsulating it over secure channel.

2.      As a service / Network secure channel, consider this example: VNC security is not the best, you can always redirect that over SSH and restrict access to loopback address.

3.      When a cable gets pulled or an access point goes out of range, addresses on the loopback never go down. This can be exploited to keep things from getting it closed if you use routing on the host to get things from real interface to loopback interface.

4.      You can put an address in loopback interface, then use BGP to advertise a / 32 route to that address to create a highly available service which would be visible with one address and is served by multiple routes and interfaces.

5.      You can use netstat-a to get it when you want to know what all ports are open on your computer, but the use of loopback interface to check what all ports are open on your computer using nmap is something different.

6.      As a system administrator, it is fairly rare to use the loopback interface. It gets used implicity from time to time, and it is extremely important for a number of reasons, but those uses and reasons are not ones that you frequently need to deal with directly as a sysadmin.

7.      The main use for the loopback interface as a sysadmin is as a very simple way that can restrict access or visibility of some service to the local computer. A service bound only to the loopback interface will only be able to open connections to, or accept connections from, the local computer.

Routing an IP address or subnet to the loopback interface is a way to blackhole an IP or subnet, although the same effect can be accomplished with IP filtering, which most system supports these days.  Should you require more information regarding this, you are free to type us at www.cloudegg.com .