You need an Application-layer firewall which can understand the traffic flowing through them and allow or deny traffic based on the content. But most business-oriented firewalls do include this capability. For Microsoft product, you can choose ISA or TMG.
Also, you can choose other products.
Microsoft is conducting an online survey to understand your opinion of the Technet Web site. If you choose to participate, the online survey will be presented to you when you leave the Technet Web site.