Since neither party appealed, the judgment entered by Judge Hall in plaintiff’s former action against defendant on the same claim became the law of the case and established the respective rights of the parties to that action. This appeal is from the order of Judge Bone. Judge Hall’s judgment in the former action was not reviewable and was not reviewed by Judge Bone in this action. Since plaintiff had commenced the present action within the time permitted by Judge Hall’s judgment, Judge Bone simply denied defendant’s motion for summary judgment.
The record on this appeal does not disclose the factual basis upon which Judge Hall quashed “the purported service of process” and “discontinued” and “dismissed” the action. The record before us does not contain the summons in the former action or any evidence or stipulation as to when and under what circumstances “the purported service of process” was made. It does appear that the clerk entered a “judgment by default and inquiry” in the former action on May 13, 1970, which he set aside by further order on May 15, 1970. It does not appear whether the “judgment by default and inquiry” entered by the clerk on May 13, 1970, was vacated by him on his own motion, on motion of defendant or by consent. Whether *580Judge Hall’s ruling was correct or erroneous, plaintiff is bound by that portion of the judgment which discontinued and dismissed the former action.
In plaintiff’s former action, in its answer to the complaint therein, defendant alleged, as one of its defenses, “that the court lacked jurisdiction over the person of the defendant and the process and service of same in said action [were] insufficient.” This answer was filed on May 15, 1970, which was within twelve months next after the inception of the loss. This plea of lack of personal jurisdiction was heard on October 15, 1970, and decided in defendant’s favor. Under these circumstances, the question arose: In dismissing the action, did Judge Hall have discretionary authority under the last sentence of Rule 41(b) to authorize plaintiff to commence a new action?
[1, 2] By dismissing plaintiff’s former action on account of defective service of process, Judge Hall in effect determined that the court, because it lacked personal jurisdiction of defendant, was unable to proceed to the merits of the case. However, in the very same judgment he also determined that Rule 41(b) gave him authority to extend the one-year limitation period and thereby give plaintiff a chance to get to the merits. Defendant contends that the second portion of the judgment is void and should be disregarded. It seeks to accept the portion of the judgment in its favor and to reject the portion thereof in plaintiff’s favor. We hold that just as plaintiff is bound by his failure to appeal, so must defendant be bound by its failure to appeal. When a defendant challenges the authority of a court on the ground it has not acquired personal jurisdiction, the court’s determination of its own jurisdiction may be questioned only by appeal and not collaterally. Baldwin v. Traveling Men’s Assn., 283 U.S. 522, 75 L.Ed. 1244, 51 S.Ct. 517 (1931); Phillips, 1970 Supplement § 939.20, to 1 McIntosh, North Carolina Practice and Procedure (2d ed.). A necessary corollary is that a judgment by a court determining its statutory authority to dismiss an action in such a way as not to bar further litigation on the merits therein may be questioned only by appeal and not collaterally. In both instances the court is specifically determining the extent of its powers. Absent appeal, all provisions of Judge Hall’s judgment are determinative as between plaintiff and defendant.
*581Treating the provisions of Rule 4(e) and the last sentence of Rule 41 (b) in pari materia, the Court of Appeals held that Judge Hall was authorized, when dismissing plaintiff’s former action, to specify that the dismissal was without prejudice and to specify in his order “that a new action based on the same claim may be commenced within one year or less after such dismissal.” Reasons tending to support this view are set forth forcefully in the opinion of Chief Judge Mallard.
On this appeal, we find it unnecessary to approve or disapprove the decision of the Court of Appeals with reference to the authority of Judge Hall under the last sentence of Rule 41 (b) to extend the time within which an action to recover on the insurance contract may be brought. On this appeal, it is unnecessary to attempt to reconcile the apparent conflict between Rule 4(e) and the last sentence of Rule 41(b). Legislative clarification seems desirable.
 On this appeal, we hold that defendant, having failed to seek appellate review, is estopped to attack in the present action that portion of Judge Hall’s judgment which granted plaintiff the right to commence a new action within thirty days.
Although based on a different ground, the decision of the Court of Appeals, which affirmed Judge Bone’s order, is affirmed.