the computer system comprising a plurality of cloud infrastructures,

each of the plurality of cloud infrastructures including a plurality of computers,

each of the plurality of computers including a hypervisor configured to manage a virtual machine created by using a resource of the each of the plurality of computers,

the virtual machine having a MAC address assigned thereto,

the hypervisor including a duplication correction virtual machine operating thereon, the duplication correction virtual machine being configured to control communication of a duplication virtual machine to which the same MAC address as the MAC address assigned to another virtual machine is assigned,

each of the plurality of cloud infrastructures further including a MAC address duplication monitoring module configured to monitor duplication of the MAC address of each of the virtual machines of the each of the plurality of cloud infrastructure and of another cloud infrastructure,

the communication control method including:

a first step of generating, by the MAC address duplication monitoring module, a translated MAC address in a case of detecting duplication of the MAC address;

a second step of transmitting, by the MAC address duplication monitoring module, a duplication correction request including the translated MAC address to one of the plurality of computers on which the duplication virtual machine operates;

a third step of generating, by the duplication correction virtual machine, translation information in which the MAC address assigned to the duplication virtual machine and the translated MAC address are associated with each other in a case of receiving the duplication correction request; and

a fourth step of controlling, by the duplication correction virtual machine, communication between the duplication virtual machine and another virtual machine by using the translation information,

wherein the MAC address duplication monitoring module is configured to hold network configuration information for managing the MAC address set in the virtual machine of each of the plurality of cloud infrastructures,

wherein the first step includes a step of determining, by the MAC address duplication monitoring module, whether the duplicated MAC address exists based on the network configuration information, and

wherein the communication control method further includes:

a step of collecting, by the MAC address duplication monitoring module, information on the MAC address assigned to each virtual machine operating on the plurality of computers included in one of the plurality of cloud infrastructures including the MAC address duplication monitoring module, and updating the network configuration information; and

a step of synchronizing, by the MAC address duplication monitoring module, the network configuration information held by the MAC address duplication monitoring module of each of the plurality of cloud infrastructures.