You can control commenting options on the “Discussion Settings” page from your dashboard for your blog.
The big decision to be made first is whether you want to allow comments at all. With WordPress, it is best to make this decision as quickly as possible after creating your blog. This is because comments are essentially enabled or disabled on a post-by-post basis, meaning you cannot simply turn comments on or off. However, on the “Discussion Settings” page, you can set the default option for all posts created from that point on. You can do this by unchecking the third checkbox, “Allow people to post comments on new articles”.
If you have not published any posts yet, this effectively disables commenting. However, if you do have published posts, the comments setting for each remains as it was when the post was published and will have to be changed manually (learn how).
If you decide to allow comments, you also have to decide whether to allow incoming and outgoing trackbacks — these are the other two default article checkboxes at the top of the “Discussion Settings” page. Trackbacks are a way to alert other blogs that you have linked to them in a post and to let you know when other blogs have linked to one of your posts. These notifications appear as comments on the respective post.
As for comments proper, you can restrict comments to only those in the VCU community by selecting the “Users must be registered and logged in to comment”. This works because you have to have a VCU eID to get a VCU WordPress account. If you want to open comments to the larger public, you can prevent anonymous comments by requiring all commenters to provide a name and email address (these are not actually validated, but the requirement may deter some ill-willed commenters).
There are a number of other options that are configurable on this screen as well. To learn more about them, please visit the WordPress Settings Discussion Screen page at the WordPress codex.