I am currently using Zabbix 2.0 in my production environment. Whenever I want to simulate a WAN outage, I create a black hole route:

ip route add blackhole 172.21.134.0/24

This will route all traffic destined towards 172.21.134.0/24 to a blackhole.

Zabbix sees this, and acts as if a WAN outage is occurring.

In zabbix 2.4.x, whenever I add the blackhole route, the ping checks that I have configured turn grey and zabbix does not see this as an outage. Additionally, the nodata() check that I have placed on the ping item does not return a failure as well.