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/82200/netreconn-1.72.tar.gz
Source: https://packetstormsecurity.com/files/82200/NetReconn-Scanning-Tool-Collection-1.72.html