[Samba] Issue writing to shares on new server

[Gregory A. Cain]

Hi -

Having had a hardware failure in our main file server, we are currently 
working off a backup server.  It's working perfectly.

I've obtained and configured the new server, but I'm having an issue 
with write permissions.

Our (Samba 3.4.0) PDC is running on Ubuntu 9.10.
Our backup server and the new server are both Samba 3.6.3 running on 
Ubuntu 12.04.1 LTS.

The smb.conf file is identical on the backup server and the new server, 
with the exception of the netbios name = directive.

Users and groups have been copied over from the backup server to the new 
server.  Everything is working fine on the backup server, but the new 
server will not allow files to be written to shares unless the read only 
= directive is turned off.

Here is a portion of the smb.conf file:

[global]
workgroup = our_workgroup
netbios name = our_fileserver
encrypt passwords = true
security = domain
server string = Main File Server
map to guest = Bad Password
guest account = nobody
printing = bsd

.
.
.

[Projects]
path=/shares/projects
comment=Project Files
browseable=yes
read only =yes
force directory mode=775
force create mode=775
force group=projects
dos filemode=yes
dos filetimes=yes
write list=@projects, at admin

Again, this is working correctly on the backup server, but people 
logging on to the "Projects" share have read-only access, even though 
they are in the projects or admin groups.

I've checked Linux permissions several times - everything is identical.

I've verified that the domain has been joined correctly, everything 
seems fine there.

Any help would be very much appreciated.

Greg