Hello everyone, I threw this same post on the apple community forums with no luck, so I'm spreading my search! Hopefully this is the right subforum for this. I'm having an issue binding a new OS X Mavericks iMac to an Active Directory domain. This is the first MAC I've ever really worked with in some time so I'm feeling kind of dumb at the moment. The first thing I want to mention is that the domain does not have a TLD. ie; it's simply named DOMAIN. Not domain.local, or domain.com, just DOMAIN. I think this might be what is causing the issue. (It's been like this since 2001~ to my knowledge). I've tried joining from both terminal using dsconfigad and the Directory Utility. It instantly fails with the following error: Error returned states: Authentication server could not be contacted. (5200) If I try it with a random TLD like DOMAIN.LOCAL, is takes some time before it errors out. If I just use DOMAIN, it fails instantly. This makes me believe the domain name is causing the issue. If this is the case, is there any way to work around the issue without having to rename my domain? I believe I've encountered a similar issue with a NAS unit running some distribution of linux. I am able to ping everything on the network by name. Time looks okay. NSLOOKUP DOMAIN displays all Domain Controllers (minus their names, just shows DOMAIN and IP, not sure if that is normal...) I have referenced this page with no luck: https://discussions.apple.com/thread/6008661?tstart=0 Any help greatly appreciated! I feel like there's some basic troubleshooting I can do that I'm missing or I'm not aware of.