Netreconn is a collection of network scan/recon tools that are relatively small compared to their larger cousins. These include nstrobe, ipdump, and ndecode.
You can download it from the following link: https://packetstormsecurity.com/files/download/93587/netrecon-1.78.tgz
Source: https://packetstormsecurity.com/files/93587/NetReconn-Scanning-Tool-Collection-1.78.html