Even if you've got a homogenous Linux or Unix server environment, at some point you are going to have a business partner, a customer or a supplier that is using Windows and is going to touch your network. And if you haven't secured those environments, then that could be a backdoor for a worm or a virus to infect your Windows network.  -   Laura DiDio     Quotes
Even if you've got a homogenous Linux or Unix server environment, at some point you are going to have a business partner, a customer or a supplier that is using Windows and is going to touch your network. And if you haven't secured those environments, then that could be a backdoor for a worm or a virus to infect your Windows network. Laura DiDio
 Environment