numa maquina em linux usa o comando "dig"
dig site_que_queres.pt
se o site existir irás receber algo tipo isto:
dig sapo.pt
; <<>> DiG 9.7.0-P1 <<>> sapo.pt
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 49242
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 2
;; QUESTION SECTION:
;sapo.pt. IN A
;; ANSWER SECTION:
sapo.pt. 80 IN A 213.13.146.140
;; AUTHORITY SECTION:
sapo.pt. 6551 IN NS ns.sapo.pt.
sapo.pt. 6551 IN NS ns2.sapo.pt.
;; ADDITIONAL SECTION:
ns.sapo.pt. 6551 IN A 212.55.154.202
ns2.sapo.pt. 1956 IN A 212.55.154.194
;; Query time: 141 msec
;; SERVER: 192.168.2.1#53(192.168.2.1)
;; WHEN: Wed May 5 21:50:27 2010
;; MSG SIZE rcvd: 108
Se não existir tens tudo em branco...
