Nmap is the most effective tool for network sweeping because it is capable of detecting active hosts, open ports, services, and even the operating system of the target hosts. It offers a wide range of scanning techniques and is one of the most comprehensive IP scanning tools available. Tracert/traceroute is mainly used for determining the path packets take to reach a host, arp relates to the Address Resolution Protocol primarily used for resolving IP addresses to MAC addresses, and curl is a command-line tool for transferring data using various network protocols, hence, they are not the best options for the described requirement of locating active hosts and open ports in this context.