(a) IN GENERAL. Process — other than a summons under Rule 4 or a subpoena under Rule 45 — must be served by a United States marshal or deputy marshal or by a person specially appointed for that purpose. It may be served anywhere within the territorial limits of the state where the district court is located and, if authorized by a federal statute, beyond those limits. Proof of service must be made under Rule 4(l).

(b) ENFORCING ORDERS: COMMITTING FOR CIVIL CONTEMPT. An order committing a person for civil contempt of a decree or injunction issued to enforce federal law may be served and enforced in any district. Any other order in a civil-contempt proceeding may be served only in the state where the issuing court is located or elsewhere in the United States within 100 miles from where the order was issued.