A communication apparatus includes a retrieval unit that retrieves a first setting information group and a second setting information group respectively from a home gateway apparatus and a DHCP server connected to a communication line, a determining unit that determines whether the setting information related to a predetermined telephone number is included in the first setting information group retrieved by the retrieval unit, an extracting unit that extracts a first type of the setting information related to the predetermined telephone number from the first setting information group, and extracts, from the second setting information group, a second type of the setting information excluding the first type of the setting information, and a communication unit that communicates with a first apparatus and a second apparatus via the communication line using the first type of the setting information and the second type of the setting information extracted by the extracting unit.