Roy Tam says to YSITD 131.140.in-addr.arpa. 172800 IN NS dns5.ntu.edu.tw. 131.140.in-addr.arpa. 172800 IN NS dns.ntu.edu.tw. ;; Received 92 bytes from 2001:500:31::63#53(x.arin.net) in 167 ms 自己不會找arin.net拿掉PTR NS紀錄喔。