"mate-network-properties" won't honor ignored-hosts address

Solution 1:

The mate-network-properties GUI focuses on the Proxy settings:

The values that are entered into "Ignored Hosts" will not run through the proxy connection. This is why the three localhost addresses are pre-filled in, as there's no point running any of those through a proxy server.

If you would like to block network traffic to Facebook (or any other service), then the simplest methods would be through the use of a hosts.deny file. Here's how you can set one up:

0. Open Terminal (if it's not already open)
1. Create the hosts.deny file:

   sudo vi /etc/hosts.deny
   

2. Add records in this format:

   ALL : .domain.com
   

   ^{Note: Do not forget that preceding . in front of the domain.}
3. Save the file
4. There is no fourth step

What's nice about this method is that you can create a single list that gets shared across multiple devices through a regular sync process. No muss. No fuss.