Systems and techniques are described for path selection. A packet can be transparently intercepted at an intermediary device. Next, the intermediary device may modify one or more bits in the header of the packet. The intermediary device can then forward the packet to the next hop device. In some network configurations, the modifications to the one or more bits in the header of the packet may cause a downstream device to select a path that is different from the path that would have been selected by the downstream device if the one or more bits in the header of the packet had not been modified. A path selection policy can be used to determine whether or not one or more bits in the header of the packet are to be modified.