This is on purpose. fping6 is no more needed. fping can do IPv4 and IPv6. Please see /usr/share/doc/fping/changelog.Debian.gz.
The reason that command-not-found suggests to install fping for fping6 sounds like an out of date apt-file database. Do you think an entry in NEWS.Debian would have helped? -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1712812 Title: In version 4.0-2 fping6 is not installed To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/fping/+bug/1712812/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs