In this paper, the capacity region of the linear deterministic interference channel with noisy channel-output feedback (LD-IC-NOF) is fully characterized. A capacity-achieving scheme is obtained using a random coding argument and three well-known techniques: rate splitting, superposition coding and backward decoding. The converse region is obtained using some of the existing outer bounds as well as a set of new outer bounds that are obtained by using genie-aided models of the original LD-IC-NOF. Using the insights gained from the analysis of the LD-IC-NOF, an achievability region and a converse region for the two-user Gaussian interference channel with noisy channel-output feedback (G-IC-NOF) are presented. Finally, the achievability region and the converse region approximate the capacity region of the G-IC-NOF to within 4.4 bits.
