if security= user and samba authentificate itself on local linux, you need to add user in linux & samba...for example: useradd fred and then smbpasswd -a fred. Samba then asks two times for password. Type pass and you should be fine. If you logon on windows like fred using password you typed adding fred to samba, then access to samba share is granted without asking you for username/pass. If you logon to windows like admin or some else user, samba asks you for username/pass when accessing share. In this case, type fred and pass. Also try access samba share from, let's say, windows workstation, or stand-alone windows (one that is not in windows domain...btw is that samba authentificate itself on AD?...if so that is problem for sure)
if nothing helps, try setting guest access in smb conf.
also..it would be fine if you post your smb.conf
best regards, hope this helps a little
