A system for filtering traffic in virtual networks includes a first virtual machine executed by a first physical server connected to a physical network and a second virtual machine executed by a second physical server connected to the physical network. The first and second virtual machines are connected to a same virtual network. A first firewall module is executed by the first physical server and a second firewall module is executed by the second physical server. The firewall modules are configured to filter network traffic received by the physical servers and addressed to the virtual servers.