SealedMail

Getting SPF, DKIM and DMARC right starts with DNS. We've written a guide on where each record lives, the hosting mistakes that break authentication, and how to check your work. https://www.sealedmail.co.uk/resources/dns-hosting-email-authentication-records/

@zeek@infosec.exchange Good tip on Zeek's MIME reassembly. Worth noting that at the protocol layer, DMARC aggregate reports are also structured XML that benefits from proper parsing rather than manual string handling. Most open-source DMARC processors will do the heavy lifting if you feed them raw report attachments cleanly.

@thecybersecguru@infosec.exchange Worth separating the two risks here. Hide My Email protects against who knows your real address, but DMARC protects against attackers spoofing your real address to others. Both matter and neither substitutes for the other.

Want your logo showing up in inboxes? BIMI is great, but authentication comes first. Check what you need to sort before rolling it out: https://www.sealedmail.co.uk/resources/bimi-your-logo-in-the-inbox-but-fix-this-first/

NCSC Mail Check is gone, but email security isn't optional. Our guide walks you through staying compliant with SPF, DKIM, and DMARC post-retirement. Everything you need to know: https://www.sealedmail.co.uk/resources/ncsc-email-security-check-your-2026-migration-guide/

DMARC protecting your main domain but not subdomains? The sp tag fixes that. Find out how to set separate subdomain policies and close the gaps in your email security. https://www.sealedmail.co.uk/resources/dmarc-subdomain-policy-sp-tag/

Tired of DMARC checker tools that demand dashboard logins or charge per domain? We've compared 4 alternatives to help you pick the right one for your needs. Check it out: https://www.sealedmail.co.uk/resources/dmarc-checker-4-alternatives/ #DMARC

DKIM failing? Your emails might be vulnerable to spoofing. We've broken down the causes, fixes, and best practices to keep your domain protected. Read the full guide: https://www.sealedmail.co.uk/resources/dkim-fail-explained-causes-fixes-and-best-practices/

@Graylog@infosec.exchange Good point about siloed telemetry. One thing worth adding: DMARC aggregate reports are another underused source of email threat visibility, showing exactly which IPs are sending on your domain's behalf, legitimate or otherwise. Feeding that into a SIEM alongside Mimecast logs gives a much fuller picture of impersonation attempts before they even reach the inbox.

@cyberseckyle@infosec.exchange Solid write-up covering the fundamentals. One practical tip worth adding: once SPF, DKIM, and DMARC are in place, keep an eye on your aggregate reports regularly. They show you who is actually sending on your behalf and will flag misconfigurations or spoofing attempts you would otherwise miss entirely.