pajus @published 2026-10-20 · 13 min read DNS Hijack to Rogue TLS Certs: CAA, CT, DNSSEC How a DNS hijack lets attackers pass ACME validation and get rogue TLS certificates, and how to limit it with CAA accounturi, CT diffs and DNSSEC. Tags TLS DNS Web Security Server Hardening
pajus @published 2026-10-18 · 11 min read DKIM, SPF and DMARC for Postfix on Debian 13 Set up DKIM, SPF and DMARC for Postfix on Debian 13 with opendkim, selector rotation, a staged DMARC rollout and checks with swaks and opendkim-testkey. Tags Email DNS Server Administration Server Hardening
pajus @published 2026-09-24 · updated 2026-10-28 · 11 min read BIND9 and Unbound Security Updates on Debian 13 Debian 13 fixes BIND9 and Unbound flaws (DSA-6505-1, DSA-6507-1): how to check versions, patch, restart and verify your recursive DNS resolver. Tags DNS Security Updates Debian Server Administration