On second thought, try creating a new DWORD registry key under
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\LanmanServer\Parameters
Name the new key "DisableStrictNameChecking" and set it to one
(1).
I will do that later today and I'll let you know.
I tried your suggestion and, assuming I made no mistakes, it had no effect on the symptoms. What I find interesting is that from a Windows machine, "dir \\nas0.tclc.org\d0" fails with some cryptic explanation about the domain name not existing, but on Fedora, "mount //nas0.tclc.org/d0 /net/nas0/d0 ..." works just fine so only Windows cares about whatever the ASUS NAS "join domain" is doing to that domain name.
I have "worked around" the problem by naming the NAS something other than "NAS0.TCLC.org" before joining the domain. This leaves "NAS0.TCLC.org" free for me to collaterally enter it into DNS and to use it in all cases but leaves me with a domain name, "NASTY.TCLC.org", for the NAS that I never even have to use. ASUS was already aware of the problem before I reported it, but they don't seem terribly excited about it, so I doubt that they are exerting much effort to diagnose and fix it. My solution is pretty non-invasive, and very easy, once you understand that it is joining the domain that causes the problem for just that one domain name, and that you never even have to use that domain name for file access activities.