Management device, method and program for monitoring video data transmitted via network

There is provided a management device comprising a network device recognition unit configured to identify at least one predetermined device in a network by judging whether the at least one predetermined device satisfies a predetermined condition, a monitoring target setting unit which sets the at least one predetermined device as a monitoring target, a judgment unit which judges whether video data is being transmitted via the network to the at least one predetermined device, a packet acquisition unit which acquires packets of the video data being transmitted to the at least one predetermined device if the judgment unit judges that the video data is being transmitted to the at least one predetermined device, a monitoring image data generating unit which generates monitoring image data based on the packets of the video data, and an output control unit which makes an output unit output the monitoring image data.