Methods and apparatus for implementing Power over Ethernet (PoE) for auxiliary power in computer systems. Under aspects of the methods, one or more voltage inputs comprising standard power input is employed by a power control component in a network interface in an apparatus such as a network adaptor board, a System on a Chip (SoC), computer server or server blade to supply power to a network controller on the apparatus when the apparatus is operating at a normal power state. To enable the apparatus to maintain network communication when operating at a reduced power state, a PoE power input derived from at least one PoE signal received at at least one Ethernet jack of the apparatus is employed to provide power to the network controller absent use or availability of the standard power input. Accordingly, the PoE power input facilitates an auxiliary power function that may be used alone or in combination with existing (as applicable) auxiliary power input when apparatus are operated in reduced power states.