HOW TO : Route traffic to loopback interface in Linux

Back in 2009 (last decade!! 🙂 ), I wrote a blog post on how you can trick windows to route traffic destined to a particular IP address to a black-hole. In it, I mentioned the command to route traffic to /dev/null in Linux was [code]<code>route ADD IP_ADDRESS_OF_MAIL_SERVER MASK</code> [/code]

I ran into a need to try it today and looks like the trick doesn’t work :). So here is the right command if you want to route traffic to the loopback (or blackhole) destined to a particular IP address [code]sudo route add -host IP_ADDRESS_OF_HOST/NETWORK_MASK lo [/code]

For example if I want to black-hole traffic destined to, I would do the following [code] sudo route add -host lo [/code]