New Expert here.
FRCP Rule 4. Summons
(1) In General. A summons must be served with a copy of the complaint. The plaintiff is responsible for having the summons and complaint served within the time allowed by Rule 4(m) and must furnish the necessary copies to the person who makes service.
(2) By Whom. Any person who is at least 18 years old and not a party may serve a summons and complaint.
(3) By a Marshal or Someone Specially Appointed. At the plaintiff's request, the court may order that service be made by a United States marshal or deputy marshal or by a person specially appointed by the court. The court must so order if the plaintiff is authorized to proceed in forma pauperis under 28 U.S.C. §1915 or as a seaman under 28 U.S.C. §1916.
(e) Serving an Individual Within a Judicial District of the United States. Unless federal law provides otherwise, an individual—other than a minor, an incompetent person, or a person whose waiver has been filed—may be served in a judicial district of the United States by:
(1) following state law for serving a summons in an action brought in courts of general jurisdiction in the state where the district court is located or where service is made; or
(2) doing any of the following:
(A) delivering a copy of the summons and of the complaint to the individual personally;
(B) leaving a copy of each at the individual's dwelling or usual place of abode with someone of suitable age and discretion who resides there; or
(C) delivering a copy of each to an agent authorized by appointment or by law to receive service of process.
Local rules: http://www.txnd.uscourts.gov/civil-rules do not allow service by mail.
As you can see, a summons cannot be served by mail.
I hope this information is helpful.