The present invention discloses methods for effective network-security inspection in virtualized environments, the methods including the steps of: providing a data packet, embodied in machine-readable signals, being sent from a sending virtual machine to a receiving virtual machine via a virtual switch; intercepting the data packet by a sending security agent associated with the sending virtual machine; injecting the data packet into an inspecting security agent associated with a security virtual machine via a direct transmission channel which bypasses the virtual switch; forwarding the data packet to the security virtual machine by employing a packet-forwarding mechanism; determining, by the security virtual machine, whether the data packet is allowed for transmission; upon determining the data packet is allowed, injecting the data packet back into the sending security agent via the direct transmission channel; and forwarding the data packet to the receiving virtual machine via the virtual switch.