Ill. Admin. Code tit. 89, § 160.85
a) The Department shall obtain information concerning:
1) the responsible relative's whereabouts, including without limitation:
2) the responsible relative's identification, including without limitation:
c) When sufficient whereabouts and identification information for service continue to exist, the Department shall cause an alias summons to issue:
The Department shall make diligent efforts to serve process upon a responsible relative when necessary to establish, modify or enforce support under Sections 160.60, 160.65 and 160.70, as follows:
(Source: Added at 17 Ill. Reg. 2272, effective February 11, 1993)