How to Analyze an Encrypted ZIP Attachment
Handle a password-protected archive without opening it on a user workstation: collection, isolation, hashes, and a documented decision.
DMARC XML Reports: Interpret Authentication Failures
Read aggregate DMARC reports, distinguish alignment from authentication, and prioritize anomalies by sending service and business impact.
SPF Permerror: Fix the DNS Lookup Limit
Trace SPF dependencies, distinguish permerror from fail, and reduce DNS lookups while testing every sending service.
SMTP 550 5.7.1: Find the Cause of an Email Rejection
A 550 5.7.1 rejection can involve recipient policy, authentication, or reputation. Use the full diagnostic and delivery traces to find the cause.
How to Use an NRD Feed to Catch Phishing Before It Lands in the Inbox
Newly registered domains are where most phishing campaigns start. This guide walks through NRD feed workflows for brand monitoring, mail gateway hygiene, and SOC triage — without treating domain age as a blunt block rule.