In telecommunications networks the problem with call forwarding restriction according to prior art is that access through call forwarding to numbers with ensuring an answer rather than possible further forwarding is not possible. The invention is based on the idea that call forwarding is allowed despite call forwarding restriction when the number to be used in forwarding the call meets special conditions set beforehand. The number is thus compared with the preset conditions and depending on the result of this comparison the call is either forwarded or not.