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By Vieta's formulas, $$\begin{array}{rl}1\cdot 2+2\cdot 3+3\cdot 1=11& =\frac{c}{a}\\ 1\cdot 2\cdot 3=6& =-\frac{d}{a}.\end{array}$$Dividing these two equations, we get $\frac{11}{6}=-\frac{c}{d},$ so $\frac{c}{d}=\boxed{-\frac{11}{6}}.$