<div dir="ltr">We make pretty extensive use of Sagan for most of our Atlas analysis. It's maybe a little less critical for our DNS measurements (as compared to say traceroutes, where interpreting things like error conditions can be convoluted), especially since, as mentioned, you can often get DNS responses to encode everything you want (i.e. NSID or hostname.bind chaos queries).<div><br></div><div>-Marcel</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Jan 16, 2020 at 7:45 AM Stephane Bortzmeyer <<a href="mailto:bortzmeyer@nic.fr">bortzmeyer@nic.fr</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">On Thu, Jan 16, 2020 at 04:33:47PM +0100,<br>
Klaus Darilion <<a href="mailto:klaus.mailinglists@pernau.at" target="_blank">klaus.mailinglists@pernau.at</a>> wrote <br>
a message of 48 lines which said:<br>
<br>
> - analyze the probe locations (ie. country, continent)<br>
<br>
Instead of analyzing it afterwards, why not directly asking probes on<br>
the place you're interested in?<br>
<br>
I often use NSID to watch anycast servers, indeed:<br>
<br>
% blaeu-resolve --requested 100 --area West --nameserver $(dig +short +nodnssec <a href="http://d.nic.fr" rel="noreferrer" target="_blank">d.nic.fr</a> A) --type SOA --nsid --displayrtt fr<br>
Nameserver 194.0.9.1<br>
[NSID: b'<a href="http://dns.th2.nic.fr" rel="noreferrer" target="_blank">dns.th2.nic.fr</a>' <a href="http://nsmaster.nic.fr" rel="noreferrer" target="_blank">nsmaster.nic.fr</a>. <a href="http://hostmaster.nic.fr" rel="noreferrer" target="_blank">hostmaster.nic.fr</a>. 2225269298 3600 1800 3600000 5400] : 34 occurrences Average RTT 146 ms<br>
[NSID: b'<a href="http://dns.fra.nic.fr" rel="noreferrer" target="_blank">dns.fra.nic.fr</a>' <a href="http://nsmaster.nic.fr" rel="noreferrer" target="_blank">nsmaster.nic.fr</a>. <a href="http://hostmaster.nic.fr" rel="noreferrer" target="_blank">hostmaster.nic.fr</a>. 2225269298 3600 1800 3600000 5400] : 3 occurrences Average RTT 100 ms<br>
[NSID: b'<a href="http://dns.nyc.nic.fr" rel="noreferrer" target="_blank">dns.nyc.nic.fr</a>' <a href="http://nsmaster.nic.fr" rel="noreferrer" target="_blank">nsmaster.nic.fr</a>. <a href="http://hostmaster.nic.fr" rel="noreferrer" target="_blank">hostmaster.nic.fr</a>. 2225269298 3600 1800 3600000 5400] : 35 occurrences Average RTT 56 ms<br>
[NSID: b'<a href="http://dns.ix1.nic.fr" rel="noreferrer" target="_blank">dns.ix1.nic.fr</a>' <a href="http://nsmaster.nic.fr" rel="noreferrer" target="_blank">nsmaster.nic.fr</a>. <a href="http://hostmaster.nic.fr" rel="noreferrer" target="_blank">hostmaster.nic.fr</a>. 2225269298 3600 1800 3600000 5400] : 4 occurrences Average RTT 116 ms<br>
[TIMEOUT] : 2 occurrences Average RTT 0 ms<br>
[NSID: b'<a href="http://dns.mrs.nic.fr" rel="noreferrer" target="_blank">dns.mrs.nic.fr</a>' <a href="http://nsmaster.nic.fr" rel="noreferrer" target="_blank">nsmaster.nic.fr</a>. <a href="http://hostmaster.nic.fr" rel="noreferrer" target="_blank">hostmaster.nic.fr</a>. 2225269298 3600 1800 3600000 5400] : 10 occurrences Average RTT 156 ms<br>
[NSID: b'<a href="http://dns.ams.nic.fr" rel="noreferrer" target="_blank">dns.ams.nic.fr</a>' <a href="http://nsmaster.nic.fr" rel="noreferrer" target="_blank">nsmaster.nic.fr</a>. <a href="http://hostmaster.nic.fr" rel="noreferrer" target="_blank">hostmaster.nic.fr</a>. 2225269298 3600 1800 3600000 5400] : 8 occurrences Average RTT 101 ms<br>
[NSID: b'<a href="http://dns.lon.nic.fr" rel="noreferrer" target="_blank">dns.lon.nic.fr</a>' <a href="http://nsmaster.nic.fr" rel="noreferrer" target="_blank">nsmaster.nic.fr</a>. <a href="http://hostmaster.nic.fr" rel="noreferrer" target="_blank">hostmaster.nic.fr</a>. 2225269298 3600 1800 3600000 5400] : 2 occurrences Average RTT 154 ms<br>
[<a href="http://nsmaster.nic.fr" rel="noreferrer" target="_blank">nsmaster.nic.fr</a>. <a href="http://hostmaster.nic.fr" rel="noreferrer" target="_blank">hostmaster.nic.fr</a>. 2225269297 3600 1800 3600000 5400] : 1 occurrences Average RTT 24 ms<br>
Test #23843409 done at 2020-01-16T15:43:10Z<br>
<br>
Note the wonders of BGP: only a minority of probes use the instance in<br>
New York City (the fastest one) :-(<br>
<br>
Note also that the last result comes from a transparent proxy,<br>
redirecting to a cache.<br>
<br>
</blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr" class="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><b>Marcel Flores, PhD</b> | <span style="color:rgb(102,102,102);font-size:12.8px">Sr. </span><span style="color:rgb(102,102,102);font-size:12.8px">Research Scientist</span></div><div dir="ltr"><font color="#ff0000"><a href="http://research.verizondigitalmedia.com" target="_blank">research.verizondigitalmedia.com</a></font> | <a href="https://www.peeringdb.com/asn/15133" target="_blank">AS15133</a><br><span style="font-size:12.8px"><font color="#666666">e:</font> </span><a href="mailto:marcel.flores@verizondigitalmedia.com" style="font-size:12.8px" target="_blank"><font color="#ff0000">marcel.flores@verizondigitalmedia.com</font></a><span style="font-size:12.8px"> </span><br><font color="#666666">13031 W Jefferson Blvd. Building 900, Los Angeles, CA 90094</font></div></div></div></div></div></div></div></div>