WAFP is a Web Application Finger Printer written in ruby using a SQLite3 DB. WAFP fetches the files given by the Finger Prints from a webserver andchecks if the checksums of those files are matching to the given checksums from the given files. This way it is able to detect the detailed version and even the build number of a web application. The results of the scan were found: “Connection refused – connect(2)” for 1 times – retrying.
Source: https://thehackernews.com/2011/11/wafp-web-application-finger-printer.html