So thanks for your kind answer. >> 2. if client received NS records(a.iana-servers.net and b.iana-servers.net) >> from root servers, how to check which DNS is fast or slow? > > only by sending queries and seeing reply.
But if I tested, I can't find any related packets. after flushing the all cache, I executed like below. $ dig @127.0.0.1 www.example.com (192.168.1.3 is dns client) 19:23:49.711259 IP 192.168.1.3.12825> 192.54.112.30.domain: 58548 [1au] A? www.example.com. (44) 19:23:49.987665 IP 192.54.112.30.domain> 192.168.1.3.12825: 58548- 0/2/3 (124) 19:23:49.987903 IP 192.168.1.3.29328> 192.112.36.4.domain: 57596% [1au] A? a.iana-servers.net. (47) 19:23:49.987971 IP 192.168.1.3.29630> 192.112.36.4.domain: 57429% [1au] A? b.iana-servers.net. (47) 19:23:50.139827 IP 192.112.36.4.domain> 192.168.1.3.29328: 57596- 0/13/16 (532) 19:23:50.140108 IP 192.112.36.4.domain> 192.168.1.3.29630: 57429- 0/13/16 (532) 19:23:50.140265 IP 192.168.1.3.11208> 192.48.79.30.domain: 56734% [1au] A? a.iana-servers.net. (47) 19:23:50.140476 IP 192.168.1.3.64270> 192.48.79.30.domain: 19705% [1au] A? b.iana-servers.net. (47) 19:23:50.207358 IP 192.48.79.30.domain> 192.168.1.3.11208: 56734- 1/5/4 A 192.0.34.43 (212) 19:23:50.207365 IP 192.48.79.30.domain> 192.168.1.3.64270: 19705- 1/5/4 A 193.0.0.236 (214) 19:23:50.207703 IP 192.168.1.3.58817> 193.0.0.236.domain: 59823 [1au] A? www.example.com. (44) 19:23:50.482477 IP 193.0.0.236.domain> 192.168.1.3.58817: 59823*- 1/2/3 A 208.77.188.166 (140) as you see, two dns serves are 192.0.34.43 and 193.0.0.236. but dns client only querys to 193.0.0.236 without any reply from 192.0.34.43. Thanks again. _________________________________________________________________ 계정의 여왕 5월! 예쁜 사진 많이 찍고, 사진 갤러리로 리사이즈와 보정, 공유까지 한번에 해결하세요! http://mswindowslive.tistory.com/5 _______________________________________________ bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
