NitWings Insights

Technical Insights

Practical field notes for teams diagnosing email deliverability, DNS authentication, sender reputation, Linux, MTA, cloud, monitoring, and DevOps failures.

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Technical knowledge system connecting email identity, secure mail flow, servers, cloud operations, monitoring, and runbooks

182 Published articles

10 Topic tracks

Operator-grade notes Focus

Technical notes

Articles on email deliverability, DNS, Linux, MTA operations, DevOps, monitoring, and incident recovery.

Built for operators

Short, practical guidance for teams that need to diagnose, repair, and run production email systems.

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Labeled Redis topology showing three Sentinel observers, replica-to-primary failover, a promoted replica, and three cluster shards

Linux, MTA & Security · Aug 4, 2026 · 31 min read

Redis Primary-Replica (Master-Slave) and Clustering

Build Redis replication, Sentinel failover, and a six-node Cluster with validation, troubleshooting, per-shard backup, and isolated recovery.

Labeled Redis CLI diagram showing TLS-authenticated access to strings, hashes, lists, sets, sorted sets, and streams

Linux, MTA & Security · Aug 4, 2026 · 33 min read

Redis CLI, Commands, Troubleshooting, and Cheat Sheet

Operate Redis safely with redis-cli, current online and classic backups, restores, troubleshooting, large-key analysis, migrations, and admin utilities.

Mail queue investigation separating deferred traffic, SMTP responses, route health, and safe diagnostic evidence

Linux, MTA & Security · Jul 20, 2026 · 3 min read

Postfix Queue Backlog: A Safe Diagnostic Runbook

Diagnose a Postfix backlog from queue age, destination groups, SMTP responses, host health, DNS, and route evidence before changing retries or concurrency.

Linux, MTA & Security · Aug 19, 2024 · 8 min read

E-mail Infrastructure

A practical guide to the clients, DNS lookups, mail servers, protocols, message formats, and mailbox systems that move email from sender to recipient.

Secured Redis data node surrounded by memory, persistence, replication, and latency monitoring paths

Linux, MTA & Security · Sep 24, 2023 · 20 min read

Redis Installation and Tuning

Install Redis on Linux, complete a safe first-run lab, then configure security, memory, persistence, tuning, monitoring, and production recovery.

One server contains two isolated database-version stacks with separate binaries, data, configuration, ports, sockets, logs, memory, services, and backup paths

Linux, MTA & Security · May 6, 2023 · 20 min read

Run Multiple MySQL Versions on One Server Safely

Run MySQL 8.4 and 9.7 safely on one Linux server with isolated containers or separate native binaries, configs, ports, sockets, data, systemd services, backups, and rollback.

Linux operator following a protected Bash execution path through quoting, expansion, conditions, functions, pipelines, parallel jobs, cleanup, and verified results

Linux, MTA & Security · Nov 14, 2022 · 2 min read

Bash Features

The table lists shell features that can help you choose between sh, csh, ksh, Bash, tcsh, Zsh, rc, and es.

A private key remains protected while its certificate request travels to a certificate authority and the signed certificate returns to a TLS server

Linux, MTA & Security · Oct 2, 2022 · 16 min read

Create a CSR Using OpenSSL: Keys, SANs, Verification, and Deployment

Generate and verify an OpenSSL certificate signing request, protect its private key, include SANs, validate the issued certificate, and deploy it safely.

A shell script moves through controlled build and distribution stages while runtime logic remains observable and secrets arrive through a separate protected path

Linux, MTA & Security · Sep 29, 2022 · 18 min read

Protecting Shell Scripts: shc, Encryption, Signing, and Runtime Secrets

Use shc, GnuPG, signatures, permissions, and runtime secret delivery honestly, with clear limits, repeatable builds, validation, and rollback.