checked on the site ,the link is not working :(
To reduce ASP.NET configuration issues on Sitecore hosts, install IIS before updating the .NET framework. Some antivirus Software can be detrimental to performance of ASP.NET applications such as Sitecore. For Sitecore hosts, use only those antivirus scanners certified for the operating system (see http://cert.veritest.com/CfWreports/server). Certain listed products may interfere with the application such as affecting HTTP data streams; Norton Antivirus is one known culprit.
We have not used this product, better to test and user with SEP 11.0
http://sdn.sitecore.net/Products/Sitecore%20V5/Sitecore%20CMS%205,-d-,3/Installation/requirements.aspx