If you're running locally (on a workstation for example) you need to communicate with the simulator from another host.
However, pinging outside should work, I don't know what might cause this. Maybe your network card doesn't support promiscuous mode, or the switch discards all packets that it receives from a "forged" MAC address (because that is what the switch thinks it sees)
Disable selinux and iptables on the linux box. Also you can't access the IP of the sim from the machine running the VM. Setting up the VM nic in promiscuous mode also will help, sorry didn't read that you tried that until now.
ok I managed to solve: we had two nic eth0 and eth1 in bond. If you use a slave nic in the simulator, then it is not capable to communicate. So we modified setup.sh in order to allow the simulator to use bond0 as its nic.