We are looking into validating address information in house for both security concerns and performance reasons. My first intuition is build a *nix box with postgres sql on a separate physical machine. Because the information needs validation in almost real-time, what should I consider?
As a side concern, what should I consider in obtaining and updating mailing address information? I know there's a few providers out there that can assist, but we are trying to avoid submitting requests over WWW for privacy concerns.