Which of the following service provides phishing protection and content filtering to manage the Internet experience on and off your network with the acceptable use or compliance policies?

OpenDNS, now known as Cisco Umbrella, is a cloud-delivered security service that provides the first line of defense against internet threats. It operates at the DNS layer, blocking requests to malicious or unwanted destinations before a connection is even established. This core functionality includes robust phishing protection, malware blocking, and granular content filtering. Organizations use it to enforce acceptable use policies and ensure compliance by controlling the types of content users can access, both on and off the corporate network. This directly matches the service described in the question.

A. Apility.io: This is a threat intelligence platform that provides data (e.g., blacklists) via API; it is not a direct content filtering or DNS protection service.
B. Malstrom: This is not a recognized, mainstream security service for content filtering or phishing protection. The name is more commonly associated with specific malware.
D. I-Blocklist: This service provides lists of IP addresses for blocking purposes, which can be used by firewalls or other tools, but it is not a comprehensive DNS filtering service.

1. Cisco. (n.d.). What is Cisco Umbrella? Cisco Official Documentation. Retrieved from https://umbrella.cisco.com/products/what-is-cisco-umbrella. The documentation states, "Cisco Umbrella is a cloud security platform that provides the first line of defense against threats on the internet... Umbrella uses the internet’s infrastructure to block malicious destinations before a connection is ever established."

2. Stallings, W., & Brown, L. (2018). Computer Security: Principles and Practice (4th ed.). Pearson. Chapter 8, Section 8.3 discusses DNS security and the use of DNS-based filtering services like OpenDNS to block access to malicious domains.