.NET 4 only on 64 bit

On a question if the system adm开发者_StackOverflow社区inistrators could install the .NET 4 framework they answered: "We're only going to install the .NET 4 framework on 64-bit machines and your servers are currently 32-bits. So no."

We didn't have any answers back on the question "Why only on 64 bits machines?"

But I'm curious what you guys think about installing .NET 4 only on a 64-bit machine. What could be the reason of that?

We are running dotNET 4.0 in production for both 32-bit and 64-bit.

It is possible that they are simply using that as a way to put pressure on everyone to upgrade as quickly as possible to the 64-bit platform for the simple reason that the processors and operating systems have security features that are simply unavailable in their 32-bit incarnations. Being able to prevent entire classes of vulnerabilities in the config of the baseline install images helps sysadmins sleep better -- but only because they have no idea how fsckd even the 64-bit platforms are with respect to the legions of well-paid black hats.