In DC electrical networks consisting of pulse-width-modulated converters, large circulating reactive power may be caused by parallel resonance among the passive filters and the parasitic elements of the interconnecting power-line cables. Such undesired circulating currents at switching frequencies and their harmonics lead to larger ripple in the network voltage, shorter component lifetime, and increased loss. In this work, the condition for such resonances is derived analytically and two suppression methods, namely, an inductor-capacitor (LC) trap filter and an L-termination filter, are proposed. Through analysis, we demonstrate that the proposed methods can guarantee resonance suppression in a generic DC network consisting of arbitrary N converters. Systematic design rules are developed. The analysis and suppression methods are validated through laboratory experiments.