Responder is a robust, open-source tool designed for network penetration testing, specializing in Link-Local Multicast Name Resolution (LLMNR), NetBIOS Name Service (NBT-NS), and Multicast DNS (mDNS) poisoning. Pre-installed on Kali Linux, Responder enables cybersecurity professionals and ethical hackers to intercept network authentication requests, capture NTLM hashes, and perform man-in-the-middle (MITM) attacks by mimicking legitimate servers. Developed by Laurent Gaffié, it targets Windows environments where LLMNR and NBT-NS are enabled by default, making it a powerful tool for credential harvesting and network security assessments.
