/etc/pam.d/common-auth
lastmod 2026-11-10created 2020-11-183 edits
/etc/pam.d/common-auth is the file holding the common authentication settings of PAM (Pluggable Authentication Modules) on Debian- and Ubuntu-based Linux. Each service's PAM configuration, such as login, su, sudo, and ssh, includes this file, so the module rules written here apply to every authentication process. It contains the password verification module pam_unix by default, and a typical change is adding pam_tally2 or pam_faillock to limit the number of failed logins.