A communication relay apparatus that relays communication between external network and internal network comprises: judgment unit that receives from terminal on external network communication start message indicative of start of communication to judge whether or not communication start message includes specific application algorithm that requests connection to specific application within internal network; acquisition unit that, if judgment unit judges that communication start message includes specific application algorithm, identifies operation type of specific application based on random number in communication start message, and acquires information about proxy that is set according to identified operation type; proxy unit that controls operation of specific application instead of terminal based on information about proxy acquired by acquisition unit; and transmission unit that inserts specific application algorithm included in communication start message in response message responsive to communication start message, and transmits response message to terminal.