Dns

A practical guide to understanding DNS resolution tiers and troubleshooting name resolution issues in Linux environments. Covers /etc/nsswitch.conf, /etc/resolv.conf, and local caching services.

Traceroute is one of the most misunderstood tools in a network engineer’s toolkit. This guide walks through how traceroute actually works, how to read the output correctly, and how to avoid the common pitfalls that lead to wrong conclusions.

Generate a fresh rndc.key and wire it into rndc.conf so your BIND name server accepts authenticated remote control commands. Covers the rndc-confgen command and the full rndc.conf structure.

Exim offers two DKIM-related toggles that work together to validate and enforce sender signatures. Setting both to On ensures your mail server actually checks incoming DKIM records and rejects messages that fail validation.

A DNS amplification attack floods a victim with forged responses by exploiting open resolvers. This post walks through iptables rules and BIND hardening steps to block the attack vector.

A practical walkthrough of how DNS resolution works, from the hierarchical name space down to the iterative query process. Includes common zone file syntax mistakes and how to avoid them.