I don’t know whether * instead of IPaddr/IPaddr in “/home/bob/Downloads *(ro,root,_squash,sync,no_substree_check)” is valid. I’ve never tried any such syntax. Mine are all in the form 192.168.###.###/255.255.255.0. Why YaST says firefwall->nfs-kernel-server not configurable I have no idea. What does
systemctl status nfs-server.service
on your server must produce output for any other computer to see its files.
When NFS is correctly configured, showmount -e output begins with
Export list for <hostname>:
Try replacing * with 192.168.11.109/255.255.255.0 in /etc/exports, then
systemctl restart nfs.server
Your systemctl status nfs.server.service output is much different, and longer, than mine, which only shows 3 SUCCESS lines, and does not have nfsv4 enabled.
I’ve only ever used nfs-server on PCs with fixed IP addresses. Servers usually don’t change IP addresses, more often providing the DHCP service that doles them out to clients. Maybe nfs-server works better (only?) on fixed IP and you should try reconfiguring your server to use it.