A protest must be delivered to the contracting officer by hand, telegram, mail, facsimile, Federal Express or other overnight delivery service, e-mail, or telephone. If a protest is made by telephone, the contracting officer must later receive a confirming letter either within the 5-day period in Sec. 121.1004(a)(1) or postmarked no later than one day after the date of the telephone protest. [61 FR 3286, Jan. 31, 1996, as amended at 69 FR 29206, May 21, 2004]