Likewise, pretty much the de facto standard in cross-platform authentication these days, has added Oracle Enterprise Linux 4 and 5, Oracle’s version of Red Hat, to the list of some 110 Linux, Unix and Mac platforms that it supports on a Microsoft network using Active Directory.

Oracle Linux now claims 2,000 customers give or take.

Ubuntu’s billionaire backer Mark Shuttleworth told The Register that Oracle is either going to have to fork Red Hat or buy Red Hat, if the business proves successful or become strategically important.

Oracle “will do one of those things within three to five years,” he prophesied.

Meanwhile, Likewise has also started supporting mainframes that use either Red Hat or Novell to authenticate to Active Directory.