From the article:

> If you want to test services running on localhost, replace enp3s0 with lo. Though some other programs on your system may Not Like It if localhost is slow, so do that at your own risk :3 (Be sure to replace enp3s0 with lo on the undo script!)

In reality, lo will hate to be slow, esp. any application working through local network sockets (cough X11 cough). I experienced this in the olden times of Fedora 4. Somehow I (or a bug) managed to route local network sockets through my eth0. The more load the card has, the slower the X11 applications were. Esp. during launch.

I had to add another card and use it for external traffic, leaving eth0 free.