This invention pertains to a cord connector that both seals and provides strain relief automatically upon wire insertion. The cord connector comprises a wire passageway through a pliable shell which seals around both the wire inserted through the passageway as well as the knock-out or wall opening into which the connector is secured. A more rigid skeleton supports this shell and is provided with appendages which permit the wire to pass through the passageway but which block or resist any removal of the wire from the passageway. Preferably the shell is over-molded over the skeleton for ease of manufacture.