pam_unix

Standard Unix authentication

$ auth required pam_unix.so

$ password required pam_unix.so sha512 shadow

$ session required pam_unix.so

$ auth required pam_unix.so nullok

pam_unix.so [options]

pam_unix provides standard Unix authentication. Uses /etc/passwd and shadow.
The module handles basic auth. Core PAM component.
pam_unix is standard Unix auth.

nullok

Allow empty passwords.

Use SHA-512 hashing.

Use shadow passwords.

Remember N passwords.

Use previous password.

Core PAM module. Configuration critical. Hash algorithm choice.

pam_unix provides traditional Unix authentication via passwd/shadow.

pam(8), passwd(5), shadow(5)