Methods, systems, and apparatus for diagnosing and optimizing an Internet Protocol television (IPTV) network are disclosed. In one aspect a method includes receiving a network address of a device; detecting a network topology associated with the device based on the network address of the device; identifying a configuration parameter setting associated with the network topology that is outside of a range of acceptable configuration parameter settings for the network topology; and providing output specifying the configuration parameter setting that is outside of the range of acceptable configuration parameter settings.