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