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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoNormal>Dear Team,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>My caching DNS server is generating log of . NS queries to ROOT Servers. <o:p></o:p></p><p class=MsoNormal>I have a hint file in my bind configuration and the same is up-to date.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>The same behavior is occurring in multiple versions of BIND (tested on 9.7, 9.9 and on 9.10).<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>It must be for some purpose (may be BIND doesn’t trust hint file and cross check it from root servers).<o:p></o:p></p><p class=MsoNormal>Can anyone put some light on this.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><u>Sample tcpdump output :-<o:p></o:p></u></p><p class=MsoNormal>15:36:42.440831 IP anydnsmby.27938 > k.root-servers.net.domain: 38907 [1au] NS? . (28)<o:p></o:p></p><p class=MsoNormal>15:36:43.241203 IP anydnsmby.52261 > f.root-servers.net.domain: 3841 [1au] NS? . (28)<o:p></o:p></p><p class=MsoNormal>15:36:43.624041 IP anydnsmby.48889 > k.root-servers.net.domain: 6314 [1au] NS? . (28)<o:p></o:p></p><p class=MsoNormal>15:36:44.424047 IP anydnsmby.65507 > c.root-servers.net.domain: 27973 [1au] NS? . (28)<o:p></o:p></p><p class=MsoNormal>15:37:42.071574 IP anydnsmby.38958 > i.root-servers.net.domain: 53519 [1au] NS? 117.240.177.150. (44)<o:p></o:p></p><p class=MsoNormal>15:40:11.121122 IP anydnsmby.7941 > i.root-servers.net.domain: 62400 [1au] NS? 1.mr. (33)<o:p></o:p></p><p class=MsoNormal>15:45:52.780062 IP anydnsmby.49432 > e.root-servers.net.domain: 54241+ [1au] NS? . (28)<o:p></o:p></p><p class=MsoNormal>15:45:59.341780 IP anydnsmby.34368 > e.root-servers.net.domain: 55928+ [1au] NS? . (28)<o:p></o:p></p><p class=MsoNormal>15:46:04.487088 IP anydnsmby.35621 > e.root-servers.net.domain: 7266+ [1au] NS? . (28)<o:p></o:p></p><p class=MsoNormal>15:46:35.453029 IP anydnsmby.62875 > i.root-servers.net.domain: 4129 [1au] NS? comp-HP. (36)<o:p></o:p></p><p class=MsoNormal>16:16:13.747955 IP anydnsmby.39690 > a.root-servers.net.domain: 8774+ [1au] NS? . (28)<o:p></o:p></p><p class=MsoNormal>16:16:20.845363 IP anydnsmby.36994 > e.root-servers.net.domain: 63433+ [1au] NS? . (28)<o:p></o:p></p><p class=MsoNormal>16:16:36.746049 IP anydnsmby.42878 > a.root-servers.net.domain: 48439+ [1au] NS? . (28)<o:p></o:p></p><p class=MsoNormal>16:16:42.060534 IP anydnsmby.41018 > j.root-servers.net.domain: 5347+ [1au] NS? . (28)<o:p></o:p></p><p class=MsoNormal>16:16:49.081649 IP anydnsmby.53661 > e.root-servers.net.domain: 54768+ [1au] NS? . (28)<o:p></o:p></p><p class=MsoNormal>16:51:14.034065 IP anydnsmby.38025 > k.root-servers.net.domain: 52771 [1au] NS? 116.73.202.141. (43)<o:p></o:p></p><p class=MsoNormal>16:51:14.835539 IP anydnsmby.19616 > i.root-servers.net.domain: 14926 [1au] NS? 116.73.202.141. (43)<o:p></o:p></p><p class=MsoNormal>17:25:16.706395 IP anydnsmby.58045 > i.root-servers.net.domain: 30880 [1au] NS? 2.mr. (33)<o:p></o:p></p><p class=MsoNormal>17:25:16.707072 IP anydnsmby.38495 > i.root-servers.net.domain: 43451 [1au] NS? 6.mr. (33)<o:p></o:p></p><p class=MsoNormal>17:25:16.707989 IP anydnsmby.35834 > i.root-servers.net.domain: 61843 [1au] NS? 3.mr. (33)<o:p></o:p></p><p class=MsoNormal>17:56:44.855060 IP anydnsmby.61903 > a.root-servers.net.domain: 23284 [1au] NS? 172.192.168.2. (42)<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Regards,<o:p></o:p></p><p class=MsoNormal>Gaurav Kansal<o:p></o:p></p></div></body></html>