Episode 143: DNS Filtering and Email Security Enhancements (Domain 4)

Certified: The CompTIA Security+ Audio Course

DNS and email are two of the most commonly exploited services in cyberattacks—and securing them requires layered, policy-driven controls. In this episode, we explore DNS filtering, which allows organizations to block access to malicious domains by intercepting or redirecting outbound queries. We discuss how threat feeds, domain reputation systems, and custom blacklists integrate into DNS resolvers to prevent phishing, malware downloads, and data exfiltration. On the email side, we cover protections like SPF, DKIM, and DMARC—protocols that verify sender identity, detect spoofed domains, and enforce message integrity. Secure email gateways provide attachment scanning, URL rewriting, and policy enforcement to prevent targeted attacks like business email compromise (BEC) or credential phishing. Together, these technologies strengthen two of the most critical gateways into any organization, helping ensure that communication channels don’t become backdoors. When you secure DNS and email, you shut down many attacks before they begin.