Conn. Gen. Stat. § 46b-363: Contest by obligor.

(a) An obligor may contest the validity or enforcement of an income-withholding order issued in another state and received directly by an employer in this state by registering the order in a tribunal of this state and filing a contest to that order as provided in sections 46b-370 to 46b-394, inclusive, or otherwise contesting the order in the same manner as if the order had been issued by a tribunal of this state.

(b) The obligor shall give notice of the contest to (1) a support enforcement agency providing services to the obligee; (2) each employer that has directly received an income-withholding order relating to the obligor; and (3) the person designated to receive payments in the income-withholding order or, if no person is designated, to the obligee.