  This paper could have been entitled "D branes and strings from flesh and
blood." We study field theoretic prototypes of D branes/strings. To this end we
consider (2+1)-dimensional domain walls in (3+1)-dimensional N=2 SQCD with
SU(2) gauge group and two quark flavors in the fundamental representation. This
theory is perturbed by a small mass term of the adjoint matter which, in the
leading order in the mass parameter, does not break N=2 supersymmetry, and
reduces to a (generalized) Fayet-Iliopoulos term in the effective low-energy
N=2 SQED. We find 1/2 BPS-saturated domain wall solution interpolating between
two quark vacua at weak coupling, and show that this domain wall localizes a
U(1) gauge field. To make contact with the brane/string picture we consider the
Abrikosov-Nielsen-Olesen magnetic flux tube in one of two quark vacua and
demonstrate that it can end on the domain wall. We find an explicit 1/4
BPS-saturated solution for the wall/flux tube junction. We verify that the end
point of the flux tube on the wall plays the role of an electric charge in the
dual (2+1)-dimensional SQED living on the wall. Flow to N=1 theory is
discussed. Our results lead us to a conjecture regarding the notorious "missing
wall" in the solution of Kaplunovsky et al.
