my task is to simulate a model with dynare. Two of my variables are drawn form a known lognormal-distribution with different support. Is there any way to do this in dynare? The only help I found is the random sample function of matlab. However, I dont know how to implement this in dynare. Moreover, I cannot define the support of the distriubtion using this function.

Indeed, it seems that you cannot define the support but you can write a small routine where if a draw falls outside your desired support it is dropped. Hope that helps.