CentOS - Aug 2007 - Help with nis password changes

I normally try not to ask questions until I have done as much research as 
possible, and again, this is the case...

Just after I thought I had my RH5 samba/nis server working fine, I come across 
the inability to update nis passwords.
>From the server as root:
passwd guest1
Changing password for user guest1.
New UNIX password:
Retype new UNIX password:
NIS password could not be changed.
passwd: all authentication tokens updated successfully


For the heck of it:

yppasswd guest1
Changing NIS acount information for guest1 on server.
Please enter root password:
Changing NIS password for guest1 on server.
Please enter new password:
Please retype new password:
Error while changing the NIS password.
The NIS password has not been changed on the server.

The server was rebooted, but that didn't help.

What am I missing?

Thanks.

Scott

On 30/08/2007, Scott Ehrlich <scott at mit.edu>
wrote:
> I normally try not to ask questions until I have done as much research as
> possible, and again, this is the case...
>
> Just after I thought I had my RH5 samba/nis server working fine, I come
across
> the inability to update nis passwords.
>
> >From the server as root:
>
> passwd guest1
> Changing password for user guest1.
> New UNIX password:
> Retype new UNIX password:
> NIS password could not be changed.
> passwd: all authentication tokens updated successfully
>
>
> For the heck of it:
>
> yppasswd guest1
> Changing NIS acount information for guest1 on server.
> Please enter root password:
> Changing NIS password for guest1 on server.
> Please enter new password:
> Please retype new password:
> Error while changing the NIS password.
> The NIS password has not been changed on the server.
>
> The server was rebooted, but that didn't help.
>
> What am I missing?
I assume yppasswdd is running on the server?

Is there anything in /var/log/messages on the server?

James Pearson