Recently, Rim et al.1 proposed an exact Dirichlet-to-Neumann (DtN) boundary condition to study the water wave motion over undulated seabed by wave diffraction. This paper focuses on linear wave interaction with a bottom-mounted body near a vertical wall. The water domain is separated into an exterior subdomain and an interior one by a virtual cylindrical surface or so-called an artificial boundary which encloses not only the original body but also its imaginary one about the vertical wall. The wave interaction with the bodies in the interior subdomain is solved by using a boundary integral equation with an exact DtN operator on the artificial boundary which is derived from a velocity potential in the exterior subdomain. Upon successful verification of the present approach by comparison with the results of ANSYS AQWA for a bottom-mounted vertical circular cylinder near the wall, the model is extended to a vertical cylinder with cross section of rounded rectangle.