Why machines in passwd anyway? [was Re: NT machine accounts in FreeBSD?]

[Peter Samuelson]

[Paul Jansen <vlaero at yahoo.com.au>]
> It seems to me that freeBSD doesn't like login names with a '$' in
> them.  Is it possible to somehow add the required NT machine account
> (machinename$) to a FreeSD system so as to allow login from and NT
> workstation to a SAMBA controlled Domain?

This brings up a nagging question I've had for awhile.

Why does Samba insist that every member machine be in /etc/passwd (or
reachable via getpwnam(), if you use nsswitch)?  Can this be changed?

Obviously it isn't using the password, shell or home directory fields.
I don't think it needs the GECOS field either.

That leaves the UID and GID fields.  But why?  Samba doesn't ever need
to `become' the machine account user, does it?

The only thing I can think of is that Samba is using the passwd file to
reserve UID numbers so it can use them for RIDs.  Is this the case?  In
this case, I would think it would be faster and not much harder for
smbpasswd to generate RIDs from somewhere else, like a smb.conf
parameter:

  trust account rids = 50000-50999

I guess what bothers me is the duplication of information.  For regular
users, I agree that they need to be in /etc/passwd as well as
smbpasswd, but machine accounts shouldn't have to appear both places.
More to the point, administrators shouldn't have to put them in both
places.

Peter