Per the Federal Rules of Civil Procedure

(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.

And also

(m) Time Limit for Service. If a defendant is not served within 90 days after the complaint is filed, the court—on motion or on its own after notice to the plaintiff—must dismiss the action without prejudice against that defendant or order that service be made within a specified time. But if the plaintiff shows good cause for the failure, the court must extend the time for service for an appropriate period. This subdivision (m) does not apply to service in a foreign country under Rule 4(f), 4(h)(2), or 4(j)(1), or to service of a notice under Rule 71.1(d)(3)(A).

(C) makes it sound like courts find ways around physically serving someone if they keep dodging it because there is a time limit.

Anal