7 Il. We begin with personal jurisdiction, along with the closely related question of venue. Defending the district court’s decision, AF Holdings contends that any consideration of such issues is premature where, as here, the as-yetunknown defendants have yet to raise these defenses. It relies primarily on Anger v. Revco Drug Co., 791 F.2d 956 (D.C. Cir. 1986), in which we reiterated the general rule that “personal jurisdiction is a matter to be raised by motion or responsive pleading.” Jd. at 958. In Anger, however, we faced a situation very different from the one we confront here. There, we considered a district court’s sua sponte dismissal of a complaint for lack of personal jurisdiction. We held that such a dismissal is improper because “before the complaint has been served and a response received, the court is not positioned to determine conclusively whether personal jurisdiction exists.” Jd. (emphasis added). In other plaintiff has no obligation to until the defendant has raised e.g., Caribbean Broadcasting Wireless PLC, 148 F.3d 1080, (“CBS’s obligation to make personal jurisdiction arose ... motion to dismiss... .”). words, to bring an action a establish personal jurisdiction that defense. See id.; accord, System, Ltd. v. Cable & 1090 (D.C. Cir. 1998) (CBS) some allegations relating to only after CCC had filed its Different principles apply where, as here, a plaintiff seeks not just to file a complaint, but instead attempts to use the machinery of the courts to force a party to comply with its discovery demands. Federal Rules of Civil Procedure 45 and 26 set forth the relevant considerations. Rule 45(d)(3)(A) requires a district court to “quash or modify a subpoena that ... Subjects a person to undue burden.” If a subpoena compels disclosure of information that is not properly discoverable,