A communication system includes a first network, a printer connected with the first network, a host device, connected with the first network, which are configured to use the printer as a network printer with a printer driver being installed therein, a second network connected with the first network via a router, and an external server device, connected with the second network, which is configured as a providing source of a first printer driver. The printer includes a downloading unit that downloads the first printer driver from the external server device via the first and second networks, a storing unit that stores the downloaded first printer driver, and a sending unit that sends the stored first printer driver to the host device via the first network. The host device includes a receiving unit that receives the first printer driver from the sending unit.