Not too long ago, Microsoft signed a deal with Novell, which showed that Redmond’s siege mentality when it comes to Linux is finally over. But now Steve Ballmer has essentially told Linux users that they’re infringing on Microsoft intellectual property. What’s going on inside Microsoft when it comes to Open Source?

Ballmer recently told a conference in Seattle that Linux infringes on Microsoft’s intellectual property, and that “we believe every Linux customer basically has an undisclosed balance-sheet liability,” according to Computerworld.

In other words, if you use Linux, you owe Microsoft money, unless you use SUSE Linux, because that’s covered by the Microsoft-Novell deal.

This flies in the face of everything else Microsoft is doing in Open Source these days. Apart from the Novell deal, Microsoft also has an Open Source lab, for testing interoperability between Open Source and Windows, has launched the Port 25 site, giving people an inside look into what’s going on at the labs, and has even invited the Mozilla crew to their offices.

So what gives with Ballmer? My hope is that this is just one more instance of Ballmer bluster. It’s no secret that he’s not an Open Source fan, and I wouldn’t be surprised if the various Open Source initiatives have gone through despite his reservations. So it may simply be a chance for him to vent.

On the other hand, if it really reflects Microsoft thinking about Open Source, it’s pretty alarming. For now, it’s best to see what Microsoft does as a company, rather than use Ballmer’s statements, as a guide to how Redmond views Open Source. And the Open Source labs, Port 25, and the Novell deal seem to indicate it’s finally “gotten” Open Source.