Agentless security of virtual machines for outbound transmissions using a network interface controller

A method of providing agentless security of virtual machines, comprising:

• intercepting, by a virtual switch filtering extension of an extensible virtual switch on a host processor, a data packet in an outbound transmission from a virtual machine to a destination device, wherein the virtual switch filtering extension is also configured to intercept data packets in inbound transmissions to the virtual machine;
• comparing, by the virtual switch filtering extension, both a source virtual port identifier and a source network interface controller (NIC) index number indicated in the data packet with entries of a firewall location table that maps virtual port identifiers and NIC index numbers to global unique identifiers (GUIDs) of virtual machines on the host processor, wherein each virtual machine on the host processor is associated with a respective GUID that is linked to a respective set of predefined rules;
• in response to determining, based on the comparing, that the source virtual port identifier and the source NIC index number correspond to a corresponding global unique identifier (GUID) of a first virtual machine on the host processor:
• retrieving a set of predefined rules linked to the corresponding GUID of the first virtual machine;
• comparing, by the virtual switch filtering extension, parameters of the data packet with protocol-specific parameters listed in the retrieved set of predefined rules;
• and
• in response to determining that the data packet is not in compliance with the set of predefined rules associated with the first virtual machine, preventing, by the virtual switch filtering extension, transmission of the data packet from the first virtual machine to the destination device.