Here is a snippet of debug out put when attempting to join the domain: Got NTLMSSP neg_flags=check_pdu: BAD SIG: got SMB signature of  00 00 00 00 00 00 00 00 ........smb_signing_good: BAD SIG: seq 1 SPNEGO login failed: Access denied libnet_Join: libnet_Join Ctx: struct libnet_Join Ctx out: struct libnet_Join Ctx In response to comment #27, I think that the problem with clients connecting to Samba version 4.3.8 on Ubuntu 14.04 may be a different problem.This may be a fix for others with the particular issue I have. This one involved users being denied access to restricted network shares.However, if the share is wide open, there are no problems. I'm working through it now and will try to decide where to post about it as I find more. 12.04.3 and am pleased and relieved to see my test Windows XP client once again able to login to the Samba NT4 style domain.It was a little difficult to select an appropriate title for this chapter.From email messages on the Samba mailing lists it is clear that many people consider the updating and upgrading of Samba to be a migration matter.
https:/Actually, the problem we are having does not appear to be related to bug #1573221.
This upgrade broke the ability for 12.04 linux clients to join a samba managed domain.
Using the usual configuration files and current domain join creds we would get on the linux client: Connection failed: NT_STATUS_When upgrading our DC from Ubuntu 13.04 to 14.04 we were also upgraded from Samba 3.6.9 to 4.3.8.
Now Ubuntu clients cannot authenticate and (as ghomem mentions) Ubuntu member servers are not able to join the domain.
Unfortunately downgrading Samba on 14.04 is not as simple as using dpkg or apt.