https://elstir.com/en/blog/ Engineering cases and infrastructure decisions, written by the people who operate them. en https://elstir.com/en/blog/what-is-dmarc/ https://elstir.com/en/blog/what-is-dmarc/ Mon, 06 Jul 2026 00:00:00 GMT Email was born without verifying the sender. SPF, DKIM and DMARC in plain terms, CEO fraud, and operated DMARC reaching 95–100% on managed domains. https://elstir.com/en/blog/antivirus-edr-xdr-mdr/ https://elstir.com/en/blog/antivirus-edr-xdr-mdr/ Mon, 29 Jun 2026 00:00:00 GMT Security's alphabet soup, explained: what each level adds and when you need it. How we apply it across more than 250 endpoints and some 50 servers. https://elstir.com/en/blog/four-backup-layers/ https://elstir.com/en/blog/four-backup-layers/ Mon, 22 Jun 2026 00:00:00 GMT Application, files, replica, full VM: each layer covers a different risk. 30-second replication for critical systems, daily copy to a second data centre. https://elstir.com/en/blog/why-own-as/ https://elstir.com/en/blog/why-own-as/ Mon, 15 Jun 2026 00:00:00 GMT Few companies our size have their own AS and IP block. What it is, why we registered it in 2009 and what the client gains — publicly verifiable.