TVS diodes for Ethernet/PoE?
Ethernet is not that different from USB.
Consider two of Littlefuse PGB1010603NR from Digikey, one on each signal to Gnd. These are found on Arduino boards, good for USB 2.0 speeds. Keep the signal path on the board from connector to receiver chip short.
https://www.littelfuse.com/data/en/data_sheets/littelfuse_pulseguard-esd_pgb1.pdf


  PulseGuard ESD Suppressors help protect sensitive
  electronic equipment against electrostatic discharge (ESD).
  They supplement the on-chip protection of integrated
  circuitry and are best suited for low-voltage, high-speed
  applications where low capacitance is important. Data ports
  utilizing such high-speed protocols as USB 2.0, IEEE1394,
  HDMI and DVI can benefit from this new technology.