[Samba] Nonfunctional linux/CIFS mounts after update (ADS / windows DC auth)

[Jeremy Allison]

On Tue, Apr 26, 2016 at 12:06:39PM -0400, Glomski, Patrick wrote:
> Greetings,
> 
> We use samba to share files to windows and linux machines and are in the
> same boat as several others recently posting to the list. When badlock
> patches came out, we updated our CentOS7 samba server (everything from
> samba to sssd to krb5 to nss was updated) and immediately had problems with
> both client types not connecting to the windows shares.
> 
> Windows machine connections were solved by using the realm
> (workgroup.com\username)
> to log in instead of the workgroup (workgroup\username). Although it's not
> clear to me as to why I need '.com' to authenticate all of a sudden, it
> functions and isn't a critical concern for this production server.
> 
> Linux machines were mounting via 'mount -t cifs -o
> user=workgroup/username'. This mount no longer functions and it appears
> (setting server log level to 10) that the authentication on the server is
> failing where it used to succeed. 'smbclient' also fails. 

Get a wireshark trace and post what error is returned please.