Dereham were 4-2 penalty shootout victors over St Neots, after the original match and the replay had both ended 1-1.
It was the second successive shootout win for Dereham, who disposed of St Ives Town in the preliminary round courtesy of a 3-0 victory on penalties following 2-2 and 3-3 draws.
Dereham's visit to The Jakemans Stadium will unfold on Saturday September 27 (kick-off 3.00pm). Full match information will be announced in due course.
The Magpies play in Ryman North, which is two levels below Vanarama Conference North.