Episode 23 — Name resolution internals: hosts, resolv.conf, nsswitch.conf, failure modes
Name resolution is a high-yield Linux+ topic because many “network outages” are actually identity lookups failing at the client. This episode explains name resolution as a layered decision process: the system chooses a lookup order, checks local sources, queries configured DNS servers, and returns an answer that applications then use for connections. You’ll learn why files like hosts, resolv.conf, and nsswitch.conf matter at exam level: they define static overrides, DNS server targets, and the lookup priority rules that determine whether a hostname resolves quickly, slowly, or never. Understanding these internals helps you read questions that mention inconsistent behavior between tools, delays before failures, or situations where one host resolves while another does not.
we translate the internals into failure modes and practical troubleshooting. You’ll practice diagnosing symptoms like “works with IP but not hostname,” “some names resolve, others time out,” and “short names fail but FQDN works,” by tying each symptom to likely configuration or service issues. We also cover common misconfig patterns: incorrect DNS servers, missing search domains, conflicting local overrides, and lookup order rules that cause unexpected results in enterprise environments. Finally, you’ll learn how to validate resolution safely: test with multiple tools, confirm which source provided the answer, and treat resolution as part of the full connectivity workflow so you do not fix DNS while the real issue is routing, firewall policy, or service binding. Produced by BareMetalCyber.com, where you’ll find more cyber audio courses, books, and information to strengthen your educational path. Also, if you want to stay up to date with the latest news, visit DailyCyber.News for a newsletter you can use, and a daily podcast you can commute with.
