The x1b pack is a series of scripts written by the author as an exercise into socket programming with perl. Included are a port scanner with banner grabbing capabilities, a DNS service enumeration script with zonetransfer, some brute forcing utilities, a CGI web scanner, and a couple of other utilities.
You can download it from the following link: https://packetstormsecurity.com/files/download/33483/x1bpackV1.tar.gz
Source: https://packetstormsecurity.com/files/33483/x1bpackV1.tar.gz.html