Parked Domains: Assess the Risk Before Blocking
Distinguish domain parking, expiration, and malicious behavior. Examine actual use and choose a restriction supported by the evidence.
RDAP: Read Domain Data During an Investigation
Use RDAP events, statuses, and contacts to document a suspicious domain without misattributing an identity or claiming an unproven compromise.
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.
Domain Reputation Monitoring: Which Changes Need Action?
Track domain reputation over time: distinguish a new phishing report from expected DNS changes, then decide what to verify before restricting access.
Browser-in-the-Browser Phishing: Detection Guide
Understand browser-in-the-browser phishing, spot fake SSO windows, detect campaign infrastructure, and reduce risk with phishing-resistant authentication.
isMalicious vs Censys: Internet Discovery and Reputation Verdicts Are Different Jobs
Censys maps what exists on the internet — hosts, certificates, open ports. isMalicious assesses what is malicious. Most teams comparing the two need the second question answered, not the first.
isMalicious vs SecurityTrails: Discovery Data and Reputation Verdicts Are Not the Same Product
SecurityTrails tells you what exists — every subdomain, every historical DNS record. isMalicious tells you what is dangerous. Most teams searching for a SecurityTrails alternative want the second half.
WHOIS Lookup for Security Investigations: Reading a Record After Redaction
Privacy services stripped the registrant name out of most WHOIS records, but the fields that matter for triage survived. Here is what a WHOIS record still tells an analyst, and how to read it.
Domain Lookup: How to Identify Malicious Websites Before They Strike
Malicious websites are the launchpad for phishing, malware distribution, and credential theft. Learn how domain lookup tools use reputation data, WHOIS analysis, and threat feeds to identify dangerous domains before your users click.