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<p class="MsoNormal">Hey all,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I often do DNS tests via RIPE ATLAS to confirm that changes and/or new additions to our anycast network haven’t created any collateral damage to our clouds and others.
<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I’ve noticed that the first several thousand probes (probe ID’s < ~6000) consistently return inaccurate/terrible/useless results to DNS tests.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Has anyone else noticed this? Has anyone else reported it to RIPE ATLAS? Any theories?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I’ll first use DNS queries coming out of Belgium as an example…<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"> My average response time from Belgium to ANY.CA-SERVERS.CA is 25.103 ms when you exclude probe ID’s < ~6000. With those probes, it’s 83.944 ms – Greater than a 300% difference?!<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The worst part is that the ‘traceroute’ functionality never seems to show this latency…so I feel powerless in fixing this brokenness from my end.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">And it’s not just traffic from Belgium, to be clear…<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"> My average response time from Ireland to ANY.CA-SERVERS.CA is 21.296 ms when you exclude probe ID’s < ~6000. With those probes, it’s 33.507 ms.<o:p></o:p></p>
<p class="MsoNormal"> My average response time from Netherlands to ANY.CA-SERVERS.CA is 22.187 ms when you exclude probe ID’s < ~6000. With those probes, it’s 77.280ms.<o:p></o:p></p>
<p class="MsoNormal"> My average response time from Poland to ANY.CA-SERVERS.CA is 43.910 ms when you exclude probe ID’s < ~6000. With those probes, it’s 89.235 ms.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">And it’s not just CIRA…<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"> The average response time from Belgium to SNS-PB.ISC.ORG is 22.883 ms when you exclude probe ID’s < ~6000. With those probes, it’s 33.169 ms.<o:p></o:p></p>
<p class="MsoNormal"> The average response time from Belgium to F.ROOT-SERVERS.NET is 15.094 ms when you exclude probe ID’s < ~6000. With those probes, it’s 23.076 ms.<o:p></o:p></p>
<p class="MsoNormal"> The average response time from Belgium to AC1.NSTLD.COM is 36.333 ms when you exclude probe ID’s < ~6000. With those probes, it’s 44.900 ms.<o:p></o:p></p>
<p class="MsoNormal"> The average response time from Belgium to A0.INFO.AFILIAS-NST.INFO is 146.38 ms when you exclude probe ID’s < ~6000. With those probes, it’s 155.70 ms.<o:p></o:p></p>
<p class="MsoNormal"> The average response time from Belgium to X.NS.DNS.BE is 67.214 ms when you exclude probe ID’s < ~6000. With those probes, it’s 83.836 ms.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I’m attaching some photos to visually show just how ineffective these probes are at measuring anything related to DNS…<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Confirmations on others seeing this, or reporting this, or moving away from RIPE ATLAS for these measurements because of this? Recommendations other than ThousandEyes (I’m not interested in paying $100K/year for what costs $500/year in
VM’s and perl scripts).<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Ideas on how to get this rectified so that these tests can be useful again?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">-Jacob Zack<o:p></o:p></p>
<p class="MsoNormal">DNS Architect – CIRA (.CA TLD)<o:p></o:p></p>
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