See instructions for using Synology as the LDAP & NFS server.
The following was applied to Xubuntu 16.04 and is based on the Ubuntu how-to as well as this one (in the somewhat likely case that some steps are missing from this explanation)
The ldap-auth-client meta package takes care of most dependencies so just sudo apt-get install ldap-auth-client ldap-utils nscd. The installer will prompt the following parameters:
Server URI: ldap://aa.bb.cc.dd (in our case a local IP)
DN: dc=aa,dc=bb,dc=cc,dc=dd__
LDAP version to use: 3
Make local root Database admin: Yes
Does the LDAP database require login? No
Root: uid=root,cn=users,dc=aa,dc=bb,dc=cc,dc=dd___
Password
Also set up /etc/nsswitch.conf to use ldap lookups by running: sudo auth-client-config -t nss -p lac_ldap.
The goal is to remotely mount the home folders on the NFS server, nevertheless they need to be populated at first use so let's sudo nano /etc/pam.d/common-session by hand and add the following line before any pam_ldap and pam_krb5 settings:
session required pam_mkhomedir.so umask=0022 skel=/etc/skel
Then finalize with sudo /etc/init.d/nscd restart.
To allow LDAP users and not only local users to show in the LightDM login greeter, the following option must be set: sudo /usr/lib/lightdm/lightdm-set-defaults --show-manual-login true. This will make login by 'Other user' possible. After a first login, LDAP users can normally be selected in the login list (although they sometimes disappear from the greeter, in which case they can be manually selected again).
The following was applied to Xubuntu 16.04 and is based on this how-to as well as on instructions from Synology and some additional advice.
Installing the client is straightforward enough : sudo apt-get install nfs-common autofs.
We will make it so that each LDAP user has its home directory defined in LDAP as /mnt/nfs/home/user, for that purpose we first create the mount point with sudo mkdir -p /mnt/nfs/home.
As per Synology's instructions, we will use an autofs executable map to automatically mount home folders when LDAP users log in. We first need to modify the main configuration template in /etc/auto.master so that it refers to our custom script for all LDAP users with our previously defined mount point:
/mnt/nfs/home program:/etc/auto.syno --timeout=300
We then create the custom script as /etc/auto.syno, modifying the LDAP server URI accordingly. Note that this script relies on the ldapsearch command provided by the ldap-utils package which we installed earlier. What it does in essence is to look for the LDAP user on the server, and to link its local home folder mount point with the remote Synology LDAP home folders of the form "/var/services/homes/@LH-domain/num/user-uid". Let us make this script executable: chmod +x /etc/auto.syno and this should fly!
(To check if it works and to show NFS exports : showmount -e server_IP.)