Nach dem Update von Debian 5.0 Lenny auf Debian 6.0 Squeeze kann es vorkommen,
dass der Versand von Emails via SMTP nicht mehr klappt.
Das liegt an Änderungenin der PAM-Library (pam.d)

Die Fehlermeldung in /var/log/auth.log sieht dann wie folgt aus:

Feb 18 14:22:58 saslauthd[7496]: PAM adding faulty module: /lib/security/pam_unix_auth.so

Feb 18 14:22:58 saslauthd[7496]: PAM unable to dlopen(/lib/security/pam_unix_acct.so): /lib/security/pam_unix_acct.so: cannot open shared object file: No such file or directory

Feb 18 14:22:58 saslauthd[7496]: PAM adding faulty module: /lib/security/pam_unix_acct.so

Feb 18 14:22:58 saslauthd[7496]: PAM unable to dlopen(/lib/security/pam_unix_passwd.so): /lib/security/pam_unix_passwd.so: cannot open shared object file: No such file or directory

Feb 18 14:22:58 saslauthd[7496]: PAM adding faulty module: /lib/security/pam_unix_passwd.so

Feb 18 14:22:58 saslauthd[7496]: PAM unable to dlopen(/lib/security/pam_unix_session.so): /lib/security/pam_unix_session.so: cannot open shared object file: No such file or directory

Feb 18 14:22:58 saslauthd[7496]: PAM adding faulty module: /lib/security/pam_unix_session.so

Feb 18 14:22:58 saslauthd[7496]: DEBUG: auth_pam: pam_authenticate failed: Module is unknown

Feb 18 14:22:58 saslauthd[7496]: do_auth: auth failure: [user=web31_info] [service=smtp] [realm=] [mech=pam] [reason=PAM auth error]

Daher muss in der Datei /etc/pam.d/smtp folgendes ersetzt werden:

alt:

auth required /lib/security/pam_unix_auth.so

account required /lib/security/pam_unix_acct.so

password required /lib/security/pam_unix_passwd.so

session required /lib/security/pam_unix_session.so

neu:

auth required /lib/security/pam_unix.so

account required /lib/security/pam_unix.so

password required /lib/security/pam_unix.so

session required /lib/security/pam_unix.so

Danach noch saslauthd und postfix neu starten:

/etc/init.d/saslauthd restart
/etc/init.d/postfix restart