Red Hat

Here is a follow-up for someone who may someday come down this path. RedHat 7 does not used idmapd so there is no idmap.conf. It uses sssd, which has a parameter ldap_id_mapping which controls how it gets uid/gid from the AD server. When ldap_id_mapping = true in sssd.conf, the RH machine will use the SID concocted by Windows. When ldap_id_mapping=false, the linux box will use the uid/gid that is contained in each user's individual AD configuration panel under the Unix Attributes tab. If you had, for example, existing local users and wanted to move them to AD, you would create their accounts in AD and use the same uid/gids in the Unix Attributes tab. So local user Joe with UID 10001 on a linux box would be set up as AD UID 10001 in AD. RedHat 7 documentation says it doesn't matter what the name is...one could be JoeDoe and the other could be Joe...all that matters is that the uid/gid match. This doesn't seem to be completely true, however, since I have group acorn (gid225) on Unix and acornx (gid225) on AD, and the directory ends up with the group "nobody." Unfortunately, Linux doesn't have a way of finding out what the two machines said to each other when they talked about gid 225 and how they determined that they weren't a match so the Linux side would substitute "nobody" for acorn. As Neil Young says, "You pay for this and they give you that."

---------- Post updated Mar 11th, 2015 at 10:24 AM ---------- Previous update was Mar 10th, 2015 at 04:21 PM ----------

Final resolution. NFS client must specify nfsvers=3 as mount option either on command line for mount command (e.g. mount -t nfs -o nfsvers=3 nfsserver:/share /data)
or in fstab.