AP Photo

WHY should you care about the domain name system (DNS)? This inherently dull bit of the internet's plumbing turns the names used to label a single server or a collection of servers (like www.economist.com, say) into machine-readable numeric addresses (like 64.14.173.20). The rub is that DNS can be easily "poisoned" so that legitimate intelligible addresses redirect users to malicious numeric ones leaving them none the wiser. This can happen within a coffeeshop network or affect an entire country's online operations. As a consequence, web surfers and e-mail readers may fall into the hands of criminals or prying government authorities who can grab passwords and intercept communications, transfer money or imprison dissidents.