I am still using static IP for my LAN not yet DHCP
server.
I have not understood your solution. Please tell me
furthermore (more detail). How should I configure my
"/etc/nsswitch.conf" file ?

Here is my "/etc/nsswitch.conf" :
"

hosts: files dns
networks: files dns

services: files
protocols: files
rpc: files
ethers: files
netmasks: files
netgroup: files
publickey: files

bootparams: files
automount: files nis
aliases: files