RFQ: blog software for inside the fence

I want to try an internal FOUO-only weblog for my organization. From what I have seen, AKO won't do it (Six months of watching my AKO site load "The weblog channel is coming soon!").

My immediate leadership is giving tacit support, and the DOIM will let me have space on a server. So which blogging application do I get?

Requirements:

• Multiple posters.
  
• Readers will have to log in to the site to read it. The admin (me) will issue userids and allow users to set passwords.
  
• If a post links to content outside the fence, the outside content's referrer log must not capture the location of my server. As WUTT!'s own Sitemeter log says, "blocked referrer." That sounds more like a function of DOIM's firewall than of the blogging application.
  

Is this even 75%-capable in Microsoft Office/Outlook?

Anyone else doing this in a green, blue, or purple environment? If so, what are you using?