Why does SystemUIServer try to talk to my router via UDP port 192?
UDP port 192 is used for Apple’s AirPort base station discovery and configuration.
SystemUIServer is responsible for the menu bar icons, including the AirPort Wi-Fi icon and its information about the wireless connection.


According to http://hints.macworld.com/article.php?story=20110105044728511, this menu bar item requests information about wireless connections to display that information in the menu bar item, and that disabling this icon stops the connections on port 192 while not actively inspecting network configuration otherwise.