Understanding Linux File Immutable Attribute

The immutable attribute prevents a file from being modified, deleted, or renamed — even by root.

Set Immutable

chattr +i /etc/resolv.conf

Remove Immutable

chattr -i /etc/resolv.conf

Check Attributes

lsattr /etc/resolv.conf

Use Cases

• Protect DNS config from being overwritten
• Prevent critical config files from accidental modification
• Security hardening — make it harder for attackers to modify key files