(c) Service of papers on the Internal Revenue Service. Whenever a paper is required or permitted to be served on the Internal Revenue Service in connection with a proceeding under this part, the paper will be served on the Internal Revenue Service's authorized representative under
§ 10.69(a)(1) at the address designated in the complaint, or at an address provided in a notice of appearance. If no address is designated in the complaint or provided in a notice of appearance, service will be made on the office(s) established to enforce this part under the authority of
§ 10.1, Internal Revenue Service, 1111 Constitution Avenue, NW., Washington, DC 20224.