Engineering Notes
Technical writing from deployment practice
Articles on securing voice platforms, sequencing cloud migrations and the operational controls that keep infrastructure available. No vendor marketing, no invented benchmarks.
Articles
Published notes
Reference
SIP, PBX and UC port reference: what to open, what to never expose
A vendor-by-vendor reference of the ports Asterisk, FreePBX, 3CX, Issabel, Yeastar, ViciDial and common SIP carriers actually need, and which of them must never face the public internet.
17 September 2026 · 8 min read
Read article →Infrastructure
Infrastructure best practices: the controls that decide whether an estate stays up
Redundancy, segmentation, patching, backup validation, monitoring and documentation — the operational foundations that separate resilient infrastructure from a fragile one.
26 August 2026 · 8 min read
Read article →Cloud
Cloud migration: sequencing a move that does not break the business
How to assess, sequence and cut over workloads to cloud or hosted infrastructure — dependency mapping, wave planning, rollback and the costs that only appear after go-live.
5 August 2026 · 10 min read
Read article →VoIP
VoIP security: hardening a SIP platform against fraud and eavesdropping
A practical hardening sequence for Asterisk, FreePBX and 3CX deployments: transport encryption, authentication, network exposure, outbound controls and monitoring.
14 July 2026 · 9 min read
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