useradd without shadow password
I am playing around a bit with passwords and in particular the shadow password, One thing that confuses me is when I try to add a password to a newly created user account with the shadow password system turned off (via pwunconv command). Everything starts out OK with the passwd command asking me for the new password and then confirming it. Then it get an error message stating "User not known to the underlying authentication module"
If I turn on the shadow password system I can add a new password but not with it turned off.
I have a feeling it might have something to do with PAM but I don't know why.
Appreciate if someone could explain this to me.