Recent advances in networks technology require from advanced technologies for monitoring and controlling weaknesses in networks. Networks are naturally dynamic systems to which a wide variety of devices are continuously connecting and disconnecting. This dynamic nature force us to maintain a constant analysis looking for weak points that can eventually disconnect the network. The detection of weak points is devoted to find which nodes must be reinforced in order to increase the safety of the network. This work tackles the $$ backslashalpha $$$α$separator problem, which aims to find a minimum set of nodes that disconnect the network in subnetworks of size smaller than a given threshold. A Variable Neighborhood Search algorithm is proposed for finding the minimum $$ backslashalpha $$$α$separator in different network topologies, comparing the obtained results with the best algorithm found in the state of the art.