Thanks a lot Chris. 2011/2/21 Chris Buxton <chris.p.bux...@gmail.com>: > That depends on the implementation. Really old versions of BIND would > have accepted the A record. However, it's not in-bailiwick, so any > name server that would accept it is very likely vulnerable to cache > poisoning. > > Current versions of BIND (probably stretching back to somewhere in the > 8.2 series) will disregard it and resolve it separately. > > Chris Buxton > BlueCat Networks > > > On 2/21/11, Terry. <te...@list.dnsbed.com> wrote: >> Hello, >> >> Please see the dig info below. ns1.dns-diy.com is the auth-server of >> duowan.com domain. >> My question is, when ns1.dns-diy.com answer with a CNAME for >> "udb.duowan.com", and the answer also include an A RR for that alias, >> how will the public DNS cache servers handle this answer? >> Will the DNS cache use this A RR as result directly, or they make a >> new request for the alias domain name udb.duowan.blogchina.org and >> find the result? >> >> Thanks! >> >> $ dig udb.duowan.com +trace >> >> ; <<>> DiG 9.4.2-P2 <<>> udb.duowan.com +trace >> ;; global options: printcmd >> . 108212 IN NS d.root-servers.net. >> . 108212 IN NS e.root-servers.net. >> . 108212 IN NS m.root-servers.net. >> . 108212 IN NS b.root-servers.net. >> . 108212 IN NS g.root-servers.net. >> . 108212 IN NS l.root-servers.net. >> . 108212 IN NS c.root-servers.net. >> . 108212 IN NS i.root-servers.net. >> . 108212 IN NS k.root-servers.net. >> . 108212 IN NS a.root-servers.net. >> . 108212 IN NS j.root-servers.net. >> . 108212 IN NS h.root-servers.net. >> . 108212 IN NS f.root-servers.net. >> ;; Received 512 bytes from 202.96.128.86#53(202.96.128.86) in 4 ms >> >> com. 172800 IN NS h.gtld-servers.net. >> com. 172800 IN NS g.gtld-servers.net. >> com. 172800 IN NS e.gtld-servers.net. >> com. 172800 IN NS c.gtld-servers.net. >> com. 172800 IN NS d.gtld-servers.net. >> com. 172800 IN NS a.gtld-servers.net. >> com. 172800 IN NS l.gtld-servers.net. >> com. 172800 IN NS f.gtld-servers.net. >> com. 172800 IN NS k.gtld-servers.net. >> com. 172800 IN NS b.gtld-servers.net. >> com. 172800 IN NS i.gtld-servers.net. >> com. 172800 IN NS m.gtld-servers.net. >> com. 172800 IN NS j.gtld-servers.net. >> ;; Received 492 bytes from 128.8.10.90#53(d.root-servers.net) in 340 ms >> >> duowan.com. 172800 IN NS ns1.dns-diy.com. >> duowan.com. 172800 IN NS ns2.dns-diy.com. >> ;; Received 204 bytes from 192.35.51.30#53(f.gtld-servers.net) in 300 ms >> >> udb.duowan.com. 90000 IN CNAME udb.duowan.blogchina.org. >> udb.duowan.blogchina.org. 5 IN A 64.38.63.4 >> ;; Received 86 bytes from 218.85.139.33#53(ns1.dns-diy.com) in 19 ms >> >> -- >> Free SmartDNS Hosting: >> http://DNSbed.com/ >> _______________________________________________ >> bind-users mailing list >> bind-users@lists.isc.org >> https://lists.isc.org/mailman/listinfo/bind-users >> > > -- > Sent from my mobile device > _______________________________________________ > bind-users mailing list > bind-users@lists.isc.org > https://lists.isc.org/mailman/listinfo/bind-users >
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