1) Yes, it is a support question. Things that are not support questions are questions more like "Is anyone using Vicidial in Yugoslavia?" LOL (moved)
2) Read the Vicidial Manager's Manual. The whole thing. You'll get the idea of how DNC is used by the system. It is a table with numbers in it. This table is checked against just before the call is actually dialed from the hopper. Instead of being dialed, it would be marked and removed from the hopper. But there's a lot more and you should read the manual.
3) Loading the entire Federal (or even a single state) DNC into Vicidial itself would bring the system to its knees having to compare to that many records when making each call! Don't load even a single area code unless it's fairly small.
4) If you want to stop paying a scrub service, you can perform these tasks fairly easily in mysql if you know what you're doing, but don't do it on the same server during work-hours because it will hammer your mysql server (there are a whole lot of numbers in the dnc!)
5) We sell a product for $300 that will install on a Vicidial server and scrub the leads ON the Vicidial server nightly. It will alternately scrub during upload, for individual lists, but it would be best to do that during a lunch break as it is heavy usage on the server to do this. Our product will allow you to download the file from donotcall.gov, upload that same file without any changes and then forget about it. Vicidial will take care of the scrubbing later that night. We also modify the system so newly uploaded leads will not be available until after scrubbing and so that you cannot dial in areas for which you do not have the DNC loaded. It also shows the last upload date for each area code with DNC data in the system. It is presently designed to accept individual area codes OR states (not the whole DNC in one list yet, no one has paid for that to be an option).
Happy Hunting
!