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</o:shapelayout></xml><![endif]--></head><body lang=ZH-CN link=blue vlink=purple style='text-justify-trim:punctuation'><div class=WordSection1><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>If frequent prefetching generating annoying traffic is the main cause, we can reduce it dramatically by setting up hidden slave on resolver side receiving notify from the popular name owner’s master server. The urgent changes are fetched only when the slave got a notify. It requires m-to-n cooperation relationship between invited resolver operators and authoritative operators, so it sounds like it does not scale well but works in a small number of popular names and popular resolvers<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Guys, do you think it sounds like a plan ?<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Davey<o:p></o:p></span></p><p class=MsoNormal><a name="_MailEndCompose"><span lang=EN-US style='color:#1F497D'><o:p> </o:p></span></a></p><div style='border:none;border-left:solid blue 1.5pt;padding:0cm 0cm 0cm 4.0pt'><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal align=left style='text-align:left'><b><span style='font-size:10.0pt;font-family:宋体'>发件人<span lang=EN-US>:</span></span></b><span lang=EN-US style='font-size:10.0pt;font-family:宋体'> dns-operations [mailto:dns-operations-bounces@dns-oarc.net] </span><b><span style='font-size:10.0pt;font-family:宋体'>代表 </span></b><span lang=EN-US style='font-size:10.0pt;font-family:宋体'>Davey Song(</span><span style='font-size:10.0pt;font-family:宋体'>宋林健<span lang=EN-US>)<br></span><b>发送时间<span lang=EN-US>:</span></b><span lang=EN-US> 2019</span>年<span lang=EN-US>4</span>月<span lang=EN-US>5</span>日<span lang=EN-US> 9:19<br></span><b>收件人<span lang=EN-US>:</span></b><span lang=EN-US> 'dns-operations'<br></span><b>主题<span lang=EN-US>:</span></b><span lang=EN-US> [dns-operations] More Aggressive prefetch for popular names<o:p></o:p></span></span></p></div></div><p class=MsoNormal align=left style='text-align:left'><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>Hi folks, <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>I’m writing to ask if any resolver operator is doing or be asked to do aggressive pre-fetch for popular names in the case of urgent changes of owners’ names. <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US>The problem space is some concerns and complains on DNS TTL which usually makes mis-configured or hacked RR stick around for long time than name owner expected. <span style='color:#222222;background:white'>TTL 1 ~2 day even hours will make huge damage (if the user based are large) and the name owner can do nothing about it but wait unless the DNS resolver can be notified to fix it.<o:p></o:p></span></span></p><p class=MsoNormal><span lang=EN-US style='color:#222222;background:white'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#222222;background:white'>I do know the context of </span><span lang=EN-US style='color:#222222'>draft<span style='background:white'>-</span>wkumari<span style='background:white'>-</span>dnsop<span style='background:white'>-</span>hammer (thanks to Mukund’s reminder<span style='background:white'>,) but it is not aggressive enough. It pre-fetch only when it is close to the end of TTL. The intuitive approach to address the problem in my mind is to prefecth the popular names every 30 seconds or less on popular resolvers. The performance optimization can be done using a separate special server other than the busy resolver.<o:p></o:p></span></span></p><p class=MsoNormal><span lang=EN-US style='color:#222222;background:white'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#222222;background:white'>I wonder If it was discussed before or any obstacle exist which make this problem unresolved. Or any performance and risk tradeoff there. Thanks in advance.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#222222;background:white'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#222222;background:white'>Best regards, <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#222222;background:white'>Davey</span><span lang=EN-US><o:p></o:p></span></p></div></div></body></html>