ZGrab is a fast, modular application-layer network scanner designed for
completing large Internet-wide surveys. ZGrab is built to work with
ZMap (ZMap identifies L4 responsive hosts, ZGrab performs in-depth, follow-up
L7 handshakes). Unlike many other network scanners, ZGrab outputs detailed
transcripts of network handshakes (e.g., all messages exchanged in a TLS
handshake) for offline analysis.