René Bon Ćirić
Principal Cloud Architect | OpenStack, KVM & SRE | RHCE
The PTR record trap: Why sovereign enterprise mail servers fail deliverability despite perfect SPF, DKIM, and DMARC configurations.
When organizations deploy their own sovereign mail server (using Exim, Postfix, or the statically compiled exu Suite in Crystal) to regain privacy...
Obsolete 1024-bit DKIM keys: Why legacy mail signatures damage enterprise deliverability and how automated 2048-bit key rotation prevents spoofing.
DomainKeys Identified Mail (DKIM) is the cryptographic cornerstone of email authenticity. By attaching a digital signature to...
The StrictHostKeyChecking blindspot: Why disabling SSH host key verification in automation invites trivial man-in-the-middle attacks across your fleet.
When automating infrastructure deployments using Ansible, CI/CD pipelines, or bastion jump hosts, engineers frequently encounter...
Kerberos ticket failures: Why establishing cross-realm trust between FreeIPA and Active Directory fails when DNS SRV records are omitted.
In hybrid enterprise environments, establishing a bidirectional or one-way cross-realm trust between an enterprise Linux identity domain...
The multi-cloud egress penalty: Why splitting application tiers and databases across different cloud providers blows out monthly infrastructure budgets.
In the pursuit of vendor diversification, high availability, or leveraging proprietary services (e.g., running analytics on...
