DAG Replication Breaks Silently: A Real Firewall Rule, Real RPC Ports, Real Fix A real, reproduced Exchange DAG failure where the main DAG port was fine but dynamic RPC ports were blocked, found in the firewall log, fixed by allowing all traffic between DAG members, with the honest false starts kept in. Oct 14, 2026 7 min read Exchange
Setting Up UFW on Ubuntu: Reading a Real Production Firewall Ruleset UFW, Uncomplicated Firewall, is the default front end for iptables and nftables on Ubuntu, and it is the fastest way... Sep 29, 2026 4 min read Linux
CVE-2026-20079: CVSS 10.0 Cisco FMC Auth Bypass Tied to Sandworm and Qilin Ransomware A perfect 10.0 severity flaw in Cisco Secure Firewall Management Center is under active exploitation, tied by Cisco Talos to... Sep 28, 2026 4 min read Security
