What is the purpose of /etc/hosts and how does DNS resolution work in Linux?

Q: What is the purpose of /etc/hosts and how does DNS resolution work in Linux?

DNS resolution order in Linux (configured in /etc/nsswitch.conf):/etc/hosts: Local overrides. Checked first. Maps hostnames to IPs without DNS lookup.DNS servers (/etc/resolv.conf): The configured nameservers are queried via UDP port 53.Common use cases for /etc/hosts: local development overrides, blocking domains by pointing to 127.0.0.1, testing service connectivity using a service name before DNS is configured. In containers, Kubernetes manages /etc/hosts via its own CoreDNS system.

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DNS resolution order in Linux (configured in /etc/nsswitch.conf):

/etc/hosts: Local overrides. Checked first. Maps hostnames to IPs without DNS lookup.
DNS servers (/etc/resolv.conf): The configured nameservers are queried via UDP port 53.

Common use cases for /etc/hosts: local development overrides, blocking domains by pointing to 127.0.0.1, testing service connectivity using a service name before DNS is configured. In containers, Kubernetes manages /etc/hosts via its own CoreDNS system.

What is the purpose of /etc/hosts and how does DNS resolution work in Linux?

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