Port knocking script/server for fedora?

[Bruno Wolff III]

On Wed, Nov 19, 2014 at 11:58:11 +0000,
  Patrick O'Callaghan <pocallaghan at gmail.com> wrote:
>
>If the main concern is ssh hacking, you might consider denyhosts (yum
>install denyhosts). It's easy to set up and seems to be effective. The
>logs make fascinating (and scary) reading.

openssh stopped supporting tcpwrappers/libwrap in version 6.7 (which 
isn't in Fedora yet), so this will stop working in the not too distant 
future unless the Fedora maintainer puts that feature back in.