Asymmetric nanopores are fabricated via ion track-etching method. Redox-sensitive moieties are immobilized on the pore walls. Functionalized pore is exposed to oxidizing (H2O2) and reducing (dithionite) agents. Redox reaction in confined geometries is monitored through changes in electrical rectification. Experiments are described theoretically using a Poisson-Nernst-Planck model.