Mounting errors in fstab while NAS is off

Solution 1:

Try changing this in /etc/fstab:

ip_nas:/folder  /mnt/folder nfs defaults    0   0

To this (this assumes that ip_nas is in your /etc/hosts file, else use IP address):

//ip_nas/folder  /mnt/folder nfs defaults,nofail,x-systemd.device-timeout=30    0   0

//192.168.x.x/folder  /mnt/folder nfs defaults,nofail,x-systemd.device-timeout=30    0   0

And see if that helps. Report back.