Dear All, I have two AD domains, one running on Windows 2000 and one running on Windows 2003. Each with XP clients, and no trust. Ihave a linux file server running samba 3 on Centos 4.2, the smb.conf file specifies that security=server, and points the password server to the operations master on the Windows 2000 domain. All clients and 2000 servers on the Windows 2000 domain, (xp or otherwise) can access the smb shares on the linux box no problem. The windows 2003 server and XP clients on that domain cannot, first time round they receive the error "The request is not supported", after adding this: client signing = auto to my smb.conf file I get the error "the filename, directory name or volume label syntax is incorrect." I tried disabling packet signing on the win2k3 box group policy - it made no difference. I disconnect the linux server from using the windows 2000 server as a password server and setup up separate smb accounts and it works fine from the win2k3 box. I believe this is something to do with packet signing but just cant seem to find out the problem. I fixed this on a previous linux server the other way round (mounting 2k3 on Linux, but can't remember how I did it), I note that that server has a /proc/fs/cifs directory where I can kill packet signing, but the new server with the current problem does not. However I don't recall installing cifs nor does it seem to be on the older server. Any ideas? Pete