  Recently, Andreev bound states in iron pnictide have been proposed as an
experimental probe to detect the relative minus sign in the $s_\pm$-wave
pairing. While previous theoretical investigations demonstrated the feasibility
of the approach, the local density of states in the midgap regime is small,
making the detection hard in experiments. We revisit this important problem
from the Bogoliubov-de Gennes Hamiltonian on the square lattice with
appropriate boundary conditions. Significant spectral weights in the midgap
regime are spotted, leading to easy detection of the Andreev bound states in
experiments. Peaks in the momentum-resolved local density of states appear and
lead to enhanced quasiparticle interferences at specific momenta. We analyze
the locations of these magic spots and propose they can be verified in
experiments by the Fourier-transformed scanning tunneling spectroscopy.
