MacBook:~ thomas$ time nslookup mail.yahoo.com 
Server:		212.27.40.241
Address:	212.27.40.241#53

Non-authoritative answer:
mail.yahoo.com	canonical name = login.yahoo.com.
login.yahoo.com	canonical name = login-global.lgg1.b.yahoo.com.
login-global.lgg1.b.yahoo.com	canonical name = eulogin.lga1.b.yahoo.com.
eulogin.lga1.b.yahoo.com	canonical name = eu-eulogin.lga1.b.yahoo.com.
Name:	eu-eulogin.lga1.b.yahoo.com
Address: 188.125.82.242
Name:	eu-eulogin.lga1.b.yahoo.com
Address: 217.146.187.123


real	0m2.350s
user	0m0.005s
sys	0m0.005s

Plus de 2 socondes ? Ce n'est plus un DNS, c'est un annuaire papier !?
Pour comparaison :

MacBook:~ thomas$ time nslookup mail.yahoo.com  8.8.8.8
Server:		8.8.8.8
Address:	8.8.8.8#53

Non-authoritative answer:
mail.yahoo.com	canonical name = login.yahoo.com.
login.yahoo.com	canonical name = login-global.lgg1.b.yahoo.com.
login-global.lgg1.b.yahoo.com	canonical name = login.lga1.b.yahoo.com.
Name:	login.lga1.b.yahoo.com
Address: 98.139.237.162


real	0m0.048s
user	0m0.005s
sys	0m0.005s