735 ILCS 5/9-107
2021 Illinois Compiled Statutes|Chapter 735 - CIVIL PROCEDURE|735 ILCS 5/ - Code of Civil Procedure.|Article IX - Eviction

 (from Ch. 110, par. 9-107)Sec. 9-107. Constructive service. If the plaintiff, his or her agent,  or attorney files an eviction action, with or without joinder of a claim for rent in the  complaint, and is unable to obtain personal service on the  defendant or unknown occupant and a summons duly issued in such action is returned  without service stating that service can not be obtained, then the  plaintiff, his or her agent or attorney may file an affidavit stating that the  defendant or unknown occupant is not a resident of this State, or has departed from this  State, or on due inquiry cannot be found, or is concealed within this  State so that process cannot be served upon him or her, and also stating the  place of residence of the defendant or unknown occupant, if known, or if  not known, that  upon diligent inquiry the affiant has not been able to ascertain the  defendant's or unknown occupant's place of residence, then in all such eviction   cases  whether or not a claim for rent is joined with the complaint for  possession, the defendant or unknown occupant may be notified by posting  and mailing of  notices; or by publication and mailing, as provided for in  Section 2-206 of this Act. However, in cases where the defendant or unknown  occupant is notified by  posting and mailing of notices or by publication and mailing, and the  defendant or unknown occupant does not appear generally, the court may rule  only on the  portion of the complaint which seeks an eviction order, and the  court shall not enter judgment as to any rent claim joined in the  complaint or enter personal judgment for any amount owed by a unit owner  for his or her proportionate share of the common expenses, however, an in  rem judgment may be entered against the unit for the amount of common expenses  due, any other expenses lawfully agreed upon or the amount of any unpaid  fine, together with reasonable attorney fees, if any, and costs. The claim  for rent may remain pending until such time as the  defendant or unknown occupant appears generally or is served with summons, but the eviction order shall be final, enforceable and appealable if the court makes  an express written finding that there is no just reason for delaying  enforcement or appeal, as provided by Supreme Court rule of this State.Such notice shall be in the name of the clerk of the court, be  directed to the defendant or unknown occupant, shall state the nature of the cause against  the defendant or unknown occupant and at whose instance issued and the time and place for  trial, and shall also state that unless the defendant or unknown occupant appears at the  time and place fixed for trial, judgment will be entered by default, and  shall specify the character  of the judgment that will be entered in such cause.  The sheriff shall  post 3 copies of the notice in 3 public places in the neighborhood of  the court where the cause is to be tried, at least 10 days prior to the  day set for the appearance, and, if the place of residence of the  defendant or unknown occupant is stated in any affidavit on file, shall at the  same time  mail one copy of the notice addressed to such defendant or unknown occupant at  such place of  residence shown in such affidavit.  On or before the day set for the  appearance, the sheriff shall file the notice with an endorsement thereon  stating the time when and places where the sheriff posted and to whom and  at what address he or she mailed copies as required by this Section.  For want  of sufficient notice any cause may be continued from time to time until  the court has jurisdiction of the defendant or unknown occupant.  (Source: P.A. 100-173, eff. 1-1-18.)