Alvaro Herrera <alvherre(at)commandprompt(dot)com> writes:
> You can authenticate users with PAM, which amounts more or less to the
> same thing.
I believe though that using PAM against /etc/shadow would require the
postmaster to run as root. You need some external authentication
server; PAM by itself isn't going to solve it. Maybe LDAP or Kerberos?
regards, tom lane