Forms pores that allow passive diffusion of small molecules across the outer membrane. (Microbial infection) It is also a receptor for the bacteriophage T2. Is the major receptor for colicin E5 (Probable). (Microbial infection) A mixed OmpC-OmpF heterotrimer is the outer membrane receptor for toxin CdiA-EC536; polymorphisms in extracellular loops 4 and 5 of OmpC confer susceptibility to CdiA-EC536-mediated toxicity. Homotrimer (PubMed:2464593, PubMed:16079137). Forms mixed heterotrimers with OmpC and with PhoE; other mixed heterotrimers are also probable (PubMed:2464593). By growth in low osmolarity conditions (low sugar or salt); activated at low osmolarity by OmpR, repressed at high osmolarity by OmpR (at protein level) (PubMed:3010044, PubMed:2464593). Levels of OmpF protein decrease in a lon/ycgE double disruption (at protein level) (PubMed:19721064). Leads to decreased susceptibility to a number of hydrophilic antibiotics including ampicillin, cefoxitin and tetracycline (PubMed:19721064). Deletion of ompF confers resistance to colicin E5 (PubMed:27723824). Belongs to the Gram-negative porin family.