Which subscription service blocks unwanted email-based threats?

The subscription service that blocks unwanted email-based threats is Spam Blocker. This service is specifically designed to identify and filter out spam emails before they reach a user's inbox. It utilizes various techniques such as content analysis, blacklists, and heuristics to detect and block unwanted or malicious emails, thereby reducing the risk of phishing attacks, malware, and other email-based threats.

In the context of ensuring email security, other options such as WebBlocker and Gateway Antivirus focus on web traffic and files respectively, which do not specifically target email threats. Similarly, Intrusion Prevention Server is aimed at identifying and preventing network-based attacks rather than email threats. Thus, the Spam Blocker is the appropriate choice for addressing unwanted email-based threats.