Can OS X 10.9 Authenticate An Active Directory User From A Different Trusted Forest

Question

I am able to authenticate with an AD account from a different trusted domain in the same forest as the domain the client is bound to on OS X 10.9. An AD account from a trusted domain in a separate forest cannot authenticate on the same client. The same AD account from the same external trusted domain in the same external forest can authenticate to a Windows 7 client bound to the same domain as the Mac client. It seems that OS X is incapable of cross forest authentication. It seems as though the directory services search path only includes the forest of the domain the client is bound to. Windows clients seem to be able to handle the referral process to a different forest, but a Mac client does not. Am I correct in this assumption? Has anyone accomplished cross forest authentication on an OS X client? If so, how? If not, what is the reason this can't be done?

Answer 1

Well, I’ve made some encouraging progress.
I’ve managed to log on!
I deleted /var/db/.AppleSetupDone while booted into the recovery volume. I then created a new local admin user and, after a much longer than usual delay, got through the account creation stuff and arrived at last in the Finder, which was sluggish as heck.
Checked user accounts, and according to system prefs they’re all there. Fired up Activity monitor and found that opendirectoryd was consuming 365%-405% CPU.
I unbound the system from our Active Directory domain, not really expecting it to work but it did. cpu load dropped to nothing.
I rebooted, was able to log in as the original local admin user (woohoo! Progress!)
Re-bound it to AD and boom CPU shot right back up.
I unbound it again and am currently backing up the drive with CCC (conversation with professor yesterday “Time Machine? What’s Time Machine?”)
If CCC dies, I’ll run DW on the original, but I’m now pretty sure my issue is a borked opendirectory database.
Plan going forward:
I’ll nuke&pave the iMac, restore the apps, but NOT users and computer settings from the CCC during the re-install, create a new local admin, re-bind to AD see what happens.
If it doesn’t go nutz again, I’ll have him log on so it creates the local directory, copy over his original user directory from the backup drive, make it his actual home on the disk again and in theory he should be ok.
It’s amazing how often just laying my problem out in public makes my brain think of new things to try :-)
I don't know if this is directly applicable to an OpenDirectory-bound system rather than Active Directory, but it might work for you.