Blog
The Denetta blog publishes sourced, practical articles on domain and email security, FortiGate auditing and IT infrastructure audits. Articles cite primary sources (RFCs, CISA KEV, FIRST EPSS) and build on the checks in Denetta’s rule repository.
How to write an SPF record: ~all, -all and lookup limit
An SPF record is a TXT record listing the servers allowed to send mail for your domain. Correct syntax, ~all vs -all and the 10 DNS lookup limit.
SPF, DKIM and DMARC in Microsoft 365, by DNS host
Setting up SPF, DKIM and DMARC for a Microsoft 365 domain: the records you need, the Defender portal path, and steps for Azure DNS, Cloudflare and Natro.
What is DKIM and how do you check it?
DKIM is the cryptographic signature of the domain sending a message. What a selector is, how to check a DKIM record, key length and the t=y flag.
What is DMARC? p=none vs quarantine vs reject
DMARC is the DNS record that tells receivers what to do with mail failing SPF and DKIM. The three policies, rua reports and a safe path to p=reject.