Bugs
Like its author, Nmap isn't perfect.  But you can help make
    it better by sending bug reports or even writing patches.  If Nmap
    doesn't behave the way you expect, first upgrade to the latest
    version available from https://nmap.org.  If the problem persists,
    do some research to determine whether it has already been
    discovered and addressed.  Try searching for the problem or error message on
    Google since that aggregates so many forums.  If nothing comes of this, create an Issue on our tracker
    (http://issues.nmap.org) and/or mail a bug report to
    <dev@nmap.org>.  If you subscribe to the nmap-dev
    list before posting, your message will bypass moderation and get
    through more quickly.  Subscribe at https://nmap.org/mailman/listinfo/dev. Please include everything
    you have learned about the problem, as well as what version of
    Nmap you are using and what operating system version it is
    running on.  Other suggestions for improving Nmap may be sent to
    the Nmap dev mailing list as well.
If you are able to write a patch improving Nmap or fixing a
    bug, that is even better!  Instructions for submitting patches or
    git pull requests are available from https://github.com/nmap/nmap/blob/master/CONTRIBUTING.md
Particularly sensitive issues such as a security reports may
    be sent directly to Nmap's author Fyodor directly at
    <fyodor@nmap.org>.  All other reports and comments
    should use the dev list or issue tracker instead because more
    people read, follow, and respond to those.
