Due to length, this posting is divided up into multiple posts.

Rule 4. Process
(a) To What Applicable. This Rule applies to all process except as otherwise provided by these rules.
(b) Issuance of Summons by Attorney or Clerk. The summons may be signed and issued by the clerk, under the seal of the court, or it may be signed and issued by the attorney for the plaintiff. Separate additional or amended summons may issue against any defendant at any time. All other process shall be issued by the clerk, except as otherwise provided in these rules.
(c) Contents of Summons. The summons shall contain the name of the court, the county in which the action is brought, the names or designation of the parties, shall be directed to the defendant, shall state the time within which the defendant is required to appear and defend against the claims of the complaint, and shall notify him that in case of his failure to do so, judgment by default may be rendered against him. If the summons is served by publication, the summons shall briefly state the sum of money or other relief demanded. The summons shall in the signature element thereof, contain the name, address, and registration number of the plaintiff's attorney, if any, and if not, the address of the plaintiff. Except in case of service by publication under Rule 4(g) or when otherwise ordered by the court, the complaint shall be served with the summons, and in all other cases service of a summons alone after the effective date of this amended rule shall not constitute service of process. In any case, where by special order personal service of summons is allowed without the complaint, a copy of the order shall be served with the summons.
(d) By Whom Served. Process may be served inside or outside this state by the sheriff of the county where the service is made, or by a deputy, or by any other person over the age of eighteen years, not a party to the action;
(e) Personal Service. Personal service shall be as follows:
(1) Upon a natural person over the age of eighteen years by delivering a copy or copies thereof to the person, or by leaving a copy or copies thereof at the person's usual place of abode, with any person over the age of eighteen years who is a member of the person's family, or at the person's usual place of business, with the person's secretary, bookkeeper, manager, or chief clerk; or by delivering a copy to an agent authorized by appointment or by law to receive service of process;
(2) Upon a natural person, between the ages of thirteen years and eighteen years, by delivering a copy thereof to the person and another copy thereof to the person's father, mother, or guardian, or if there be none in the state, then by delivering a copy thereof to any person in whose care or control the person may be; or with whom the person resides, or in whose service the person is employed; and upon a natural person under the age of thirteen years by delivering a copy to the person's father, mother, or guardian, or if there be none in the state, then by delivering a copy thereof to the person in whose care or control the person may be.
(3) Upon a person for whom a conservator has been appointed, by delivering a copy thereof to such conservator;
(4) Upon a partnership, or other unincorporated association, by delivering a copy thereof to one or more of the partners or associates, or a managing or general agent thereof;
(5) Upon a private corporation, by delivering a copy thereof to any officer, manager, general agent, or registered agent. If no such officer or agent can be found in the county in which the action is brought, such copy may be delivered to any stockholder, agent, member, or principal employee found in such county. If such service is upon a person other than an executive officer, the secretary, general agent, or registered agent, then the clerk shall mail a copy thereof to the corporation at its last known address, at least twenty days before default is entered;
(6) Upon a municipal corporation, by delivering a copy thereof to the mayor, city manager, clerk, or deputy clerk of such corporation;
(7) Upon a county, by delivering a copy thereof to the county clerk, chief deputy, county commissioner, or designee authorized to accept service of process;
(8) Upon a school district, by delivering a copy thereof to the superintendent or to any other employee authorized to accept service of process;
(9) Upon the state by delivering a copy thereof to the attorney general, or to any employee in his office designated by him to accept service of process;
(10) (A) Upon an officer, agent, or employee of the state, acting in his official capacity, by delivering a copy thereof to the officer, agent, or employee, and by delivering a copy to the attorney general, or to any employee in his office designated by him to accept service of process.
(B) Upon a department or agency of the state, subject to suit, by delivering a copy thereof to the principal officer, chief clerk, or other executive employee thereof, and by delivering a copy to the attorney general, or any employee in his office designated by him to accept service of process.
(C) For all purposes the date of service upon the officer, agent, employee, department, or agency shall control, except that failure to serve copies upon the attorney general within three days of service upon the officer, agent, employee, department, or agency shall extend the time within which the officer, agent, employee, department, or agency must file a responsive pleading for sixty days beyond the time otherwise provided by these Rules.
(f) [RESERVED]
(g) Other Service. Service by mail or publication shall be allowed only in actions affecting specific property or status or other proceedings in rem. The party desiring service of process by publication or mail shall file a motion verified by the oath of such party or of someone in the party's behalf for an order of service by mail or publication. It shall state the facts authorizing such service, and shall show the efforts, if any, that have been made to obtain personal service and shall give the address, or last known address, of each person to be served or shall state that the address and last known address are unknown. The court shall hear the motion ex parte and, if satisfied that due diligence has been used to obtain personal service or that efforts to obtain the same would have been to no avail, shall:
(1) Order the clerk to send by registered or certified mail a copy of the process addressed to such person at such address, requesting a return receipt signed by the addressee only. Such service shall be complete on the date of the filing of the clerk's proof thereof, together with such return receipt attached thereto signed by such addressee, or
(2) Order publication of the process in a newspaper published in the county in which the action is pending. Such publication shall be made for four weeks. Within fifteen days after the order the clerk shall mail a copy of the process to each person whose address or last known address has been stated in the motion. Service shall be complete on the day of the last publication. If no newspaper is published in the county, the court shall designate one in some adjoining county.
(h) Manner of Proof.
(1) If served in a state or territory of the United States by a sheriff or United States marshal, or a deputy, by such person's certificate with a statement as to date, place, and manner of service;
(2) If by any other person, by the person's affidavit thereof, with the same statement;
(3) If by mail, by the certificate of the clerk showing the date of the mailing, and the date the clerk received the return receipt;
(4) If by publication, by the affidavit of publication, together with the certificate of the clerk as to the mailing of copy of the process where required;
(5) By the written admission or waiver of service by the person or persons to be served, duly acknowledged.
(i) Waiver of Service of Summons. A defendant who waives service of a summons does not thereby waive any objection to the venue or to the jurisdiction of the court over the person of the defendant.
(j) Amendment. At any time in its discretion and upon such terms as it deems just, the court may allow any process or proof of service thereof to be amended, unless it clearly appears that material prejudice would result to the substantial rights of the party against whom the process is issued.
(k) Refusal of Copy. If a person to be served refuses to accept a copy of the process, service shall be sufficient if the person serving the process knows or has reason to identify the person who refuses to be served, identifies the documents being served and offers to deliver a copy of the documents to the person who refuses to be served.
Source: Entire rule amended and adopted, April 30, 1997, effective July 1, 1997.
Cross references: For service of process upon any person subject to the jurisdiction of the courts of Colorado, see § 13-1-125; for subpoenas, see C.R.C.P. 45; for attachments, see C.R.C.P. 102; for garnishments, see C.R.C.P. 103; for replevin, see C.R.C.P. 104; for performance of the duties of the sheriff by the coroner when the former is a party to the action, see § 30-10-605; for publication of legal notices, see part 1 of article 70 of title 24; for certificates made in name of officer, see C.R.C.P. 110(c); for parties, see C.R.C.P. 17 to 25.
I. GENERAL CONSIDERATION.
Knowledge of a defendant of the pendency of an action cannot be substituted for service of process, for courts acquire jurisdiction in actions "in rem" as well as in actions "in personam" by lawful service of lawful process or by voluntary appearance. Weber v. Williams, 137 Colo. 269, 324 P.2d 365 (1958).
A judgment rendered without service, or upon the unauthorized appearance of an attorney, is void, and all proceedings had thereunder are as to all persons, irrespective of notice or bona fides, absolute nullities. Weber v. Williams, 137 Colo. 269, 324 P.2d 365 (1958).
Absence of legal service or authorized appearance is jurisdictional, and, without jurisdiction, no judgment whatever will be entered, nor rights acquired thereunder. Weber v. Williams, 137 Colo. 269, 324 P.2d 365 (1958); United Bank of Boulder, N.A. v. Buchanan, 836 P.2d 473 (Colo. App. 1992).
When jurisdiction has been obtained by the service of process, actual or constructive, all subsequent proceedings are an exercise of jurisdiction, and however erroneous, they are not void, but voidable only, and not subject to collateral attack. Brown v. Tucker, 7 Colo. 30, 1 P. 221 (1883).
It is not incumbent upon a defendant to do anything to make service of process upon him valid or regular. Coppinger v. Coppinger, 130 Colo. 175, 274 P.2d 328 (1954); Weber v. Williams, 137 Colo. 269, 324 P.2d 365 (1958).
Proper service question of fact. Whether personal or substituted service on a party has been properly made is a question of fact to be resolved by the trial court. Stubblefield v. District Court, 198 Colo. 569, 603 P.2d 559 (1979); People in Interest of S.C., 802 P.2d 1101 (Colo. App. 1989).
Service on wrong person confers no jurisdiction. Where the person intended to be sued is named as defendant and service is had on a different person who is not acting for, nor an agent of, the defendant, such service confers no jurisdiction over either the person named in the process or the person actually served. Havens v. Hardesty, 43 Colo. App. 162, 600 P.2d 116 (1979).
Distinction between subject-matter jurisdiction and personal jurisdiction. Long-arm statute, § 13-1-124, together with defendant's note submitting to jurisdiction of Colorado courts for purposes of enforcement, conferred subject-matter jurisdiction. However, in absence of valid service of process, court lacked personal jurisdiction and judgment was void. United Bank of Boulder, N.A. v. Buchanan, 836 P.2d 473 (Colo. App. 1992).
An objection to lack of personal jurisdiction relates to the power of a court to compel a defendant to appear and to defend or face entry of a default judgment. And, an objection to service of process is directed to the manner of notifying a defendant that a plaintiff seeks to have a court exercise personal jurisdiction over the defendant. United Bank of Boulder, N.A. v. Buchanan, 836 P.2d 473 (Colo. App. 1992).

III. ISSUANCE OF SUMMONS AND OTHER PROCESS.
Law reviews. For article, "The Federal Rules from the Standpoint of the Colorado Code", see 17 Dicta 170 (1940).
Annotator's note. Since section (5) of this rule is similar to § 35 of the former Code of Civil Procedure, which was supplanted by the rules of civil procedure in 1941, relevant cases construing that section have been included in the annotations to this rule.
The summons provided for by this rule is not a writ or process within the meaning of the constitution; there is no definition of "process", given by any accepted authority, which implies that any writ or method by which a suit is commenced is necessarily "process". A party is entitled to notice and to a hearing under the constitution before he can be affected, but it is nowhere declared or required that such notice shall be only a writ issuing out of a court. Comet Consol. Mining Co. v. Frost, 15 Colo. 310, 25 P. 506 (1890).
A summons may be signed by an attorney and need not be under seal of court. Rand v. Pantagraph Co., 1 Colo. App. 270, 28 P. 661 (1891).
When a clerk has been appointed by a judge, so long as the appointment is not revoked, the clerk or his deputy alone has power to discharge the clerical duties of the office, and a summons issued and signed by the judge is void, notwithstanding the disqualification of the clerk to act on account of absence or sickness. McNevins v. McNevins, 28 Colo. 245, 64 P. 199 (1901).
A judge may elect to perform the duties of clerk of his court, and, when he does so elect, he is authorized to issue and sign all processes from his court. McNevins v. McNevins, 28 Colo. 245, 64 P. 199 (1901).
A summons not issued and signed either by the clerk or plaintiff's attorney is no summons. Russell v. Craig, 10 Colo. App. 428, 51 P. 1017 (1897).
The service of an unsigned summons does not effectively bring defendants within the jurisdiction of the court. Brown v. Amen, 147 Colo. 468, 364 P.2d 735 (1961).
An acceptance of service of a purported summons which was signed by neither the clerk nor plaintiff's attorney would be no acceptance of service of summons. Russell v. Craig, 10 Colo. App. 428, 51 P. 1017 (1897).
Entry of appearance by defendant to an action waives objections to summons or service thereof. Russell v. Craig, 10 Colo. App. 428, 51 P. 1017 (1897); see Brown v. Amen, 147 Colo. 468, 364 P.2d 735 (1961).
Summons issued upon a defective, but amendable, complaint is not void. A complaint which is defective, but amendable, cannot be regarded as entirely void, nor can a summons be so regarded merely because it is issued upon such a complaint. And it is of no importance that a copy of the original complaint was attached to the summons as served upon the respondents, because they are bound to take notice of the rule relating to amendments, and, if they choose to act on the assumption either that the plaintiff would not seek an amendment or that the court would not permit one, they do so at their peril. Goodman v. City of Ft. Collins, 164 F. 970 (8th Cir. 1908).