US Patent 7949762 Address managing method and communication apparatus

A communication apparatus establishes a one-way data connection and a connection to a network in which messages are transferred in two ways, and includes: a one-way data connection status detecting unit which detects a connection validating request indicating a communication apparatus on a data reception side that data transmission, utilizing the one-way data connection, is possible and a connection invalidating request indicating that the data transmission is impossible, both of which are outputted from the communication apparatus on the data reception side; an apparatus address obtaining unit which obtains an apparatus address with a message via the network when a change from the connection invalidating request to the connection validating request is detected; an address holding unit which holds the apparatus address; and a message transmission continuing unit which responds to the message received via the network based on the apparatus address held by the address holding unit regardless of whether or not the connection invalidating request is detected.