I accidentally found that "nslookup" works even if I specify a
non-existent dns server. For example "lookup www.kingoffighters.com
202.30.50.1" will return nothing for the first time but return correct
result for the second. 202.30.50.1 is just a random typed address. Is
this normal?

full log：
nslookup www.kingoffighters.com 202.30.50.1
DNS request timed out.
timeout was 2 seconds.
*** Can't find server name for address 202.30.50.1: Timed out
Server: UnKnown
Address: 202.30.50.1

DNS request timed out.
timeout was 2 seconds.
DNS request timed out.
timeout was 2 seconds.
*** Request to UnKnown timed-out

nslookup www.kingoffighters.com 202.30.50.1
DNS request timed out.
timeout was 2 seconds.
*** Can't find server name for address 202.30.50.1: Timed out
Server: UnKnown
Address: 202.30.50.1

DNS request timed out.
timeout was 2 seconds.
Non-authoritative answer:
Name: www.kingoffighters.com
Address: 50.63.202.64
--
Regards,
Lu Wei
IM:
PGP: 0xA12FEF7592CCE1EA