According to
/etc/resolv.conf a name lookup should first use your 192.168.100.200 local nameserver but for some reason it does not.
The
nslookup command shows that the secondary fallback nameserver 8.8.8.8 nameserver of Google, which does not know anything about your local/private "laboratorio.local" domain, is being used.
Have you checked with
$ netstat -an -f inet that your local nameserver is running and LISTENing on port 53 for both UDP and TCP?
See
http://daemonforums.org/showthread.php?t=4471#post30543 for an example of what you should look for.