<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
</head>
<body text="#000000" bgcolor="#FFFFFF">
<p>But notice that their infrastructure servers do have reverse DNS.
I don't know that I really have an ask here, other than an
observation that it's nice when DNS works; and when it doesn't
it's not that difficult to synthesize PTR records from observed
traffic. (Further editorializing deleted.)<br>
</p>
<p>--</p>
<p>Fred Morris</p>
<p>--<br>
</p>
<pre># dig cloudflare-dns.com
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 35599
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 3, ADDITIONAL: 7
;; QUESTION SECTION:
;cloudflare-dns.com. IN A
;; ANSWER SECTION:
cloudflare-dns.com. 82 IN A 104.16.248.249
cloudflare-dns.com. 82 IN A 104.16.249.249
;; AUTHORITY SECTION:
cloudflare-dns.com. 171975 IN NS ns2.cloudflare-dns.com.
cloudflare-dns.com. 171975 IN NS ns1.cloudflare-dns.com.
cloudflare-dns.com. 171975 IN NS ns3.cloudflare-dns.com.
;; ADDITIONAL SECTION:
ns1.cloudflare-dns.com. 171975 IN A 162.159.0.33
ns2.cloudflare-dns.com. 171975 IN A 162.159.1.33
ns3.cloudflare-dns.com. 171975 IN A 162.159.2.9
ns1.cloudflare-dns.com. 171975 IN AAAA 2400:cb00:2049:1::a29f:21
ns2.cloudflare-dns.com. 171975 IN AAAA 2400:cb00:2049:1::a29f:121
ns3.cloudflare-dns.com. 171975 IN AAAA 2400:cb00:2049:1::a29f:209
</pre>
<pre># dig -x 104.16.248.249
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 60630
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1
;; QUESTION SECTION:
;249.248.16.104.in-addr.arpa. IN PTR
;; AUTHORITY SECTION:
16.104.in-addr.arpa. 3600 IN SOA cruz.ns.cloudflare.com. dns.cloudflare.com. 2288625500 10000 2400 604800 3600
</pre>
<pre># dig mozilla.cloudflare-dns.com
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 56983
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 2, ADDITIONAL: 7
;; QUESTION SECTION:
;mozilla.cloudflare-dns.com. IN A
;; ANSWER SECTION:
mozilla.cloudflare-dns.com. 300 IN A 172.64.41.4
mozilla.cloudflare-dns.com. 300 IN A 162.159.61.4
;; AUTHORITY SECTION:
mozilla.cloudflare-dns.com. 299 IN NS dorthy.ns.cloudflare.com.
mozilla.cloudflare-dns.com. 299 IN NS terin.ns.cloudflare.com.
;; ADDITIONAL SECTION:
terin.ns.cloudflare.com. 85645 IN A 108.162.193.236
terin.ns.cloudflare.com. 85645 IN A 172.64.33.236
terin.ns.cloudflare.com. 85645 IN A 173.245.59.236
dorthy.ns.cloudflare.com. 85645 IN A 108.162.192.249
dorthy.ns.cloudflare.com. 85645 IN A 172.64.32.249
dorthy.ns.cloudflare.com. 85645 IN A 173.245.58.249
</pre>
<pre># dig -x 172.64.41.4
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 27383
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1
;; QUESTION SECTION:
;4.41.64.172.in-addr.arpa. IN PTR
;; AUTHORITY SECTION:
64.172.in-addr.arpa. 2948 IN SOA cruz.ns.cloudflare.com. dns.cloudflare.com. 2280027582 10000 2400 604800 3600
</pre>
<pre># dig -x 162.159.0.33
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 7716
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 7
;; QUESTION SECTION:
;33.0.159.162.in-addr.arpa. IN PTR
;; ANSWER SECTION:
33.0.159.162.in-addr.arpa. 1800 IN PTR ns3.cloudflare.com.
</pre>
<pre># dig cruz.ns.cloudflare.com
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 41140
;; flags: qr rd ra; QUERY: 1, ANSWER: 3, AUTHORITY: 5, ADDITIONAL: 21
;; QUESTION SECTION:
;cruz.ns.cloudflare.com. IN A
;; ANSWER SECTION:
cruz.ns.cloudflare.com. 86353 IN A 172.64.32.88
cruz.ns.cloudflare.com. 86353 IN A 108.162.192.88
cruz.ns.cloudflare.com. 86353 IN A 173.245.58.88
</pre>
<pre># dig -x 172.64.32.88
; <<>> DiG 9.12.3-P1 <<>> -x 172.64.32.88
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 31715
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 10
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1280
; COOKIE: 44c3fd36426feb1af0830e666509ca1431cd55e8888dcc1f (good)
;; QUESTION SECTION:
;88.32.64.172.in-addr.arpa. IN PTR
;; ANSWER SECTION:
88.32.64.172.in-addr.arpa. 1800 IN PTR cruz.ns.cloudflare.com.
;; AUTHORITY SECTION:
64.172.in-addr.arpa. 1374 IN NS cruz.ns.cloudflare.com.
64.172.in-addr.arpa. 1374 IN NS kevin.ns.cloudflare.com.
# dig one.one.one.one
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4317
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 2, ADDITIONAL: 7
;; QUESTION SECTION:
;one.one.one.one. IN A
;; ANSWER SECTION:
one.one.one.one. 300 IN A 1.0.0.1
one.one.one.one. 300 IN A 1.1.1.1
;; AUTHORITY SECTION:
one.one.one. 2067 IN NS terin.ns.cloudflare.com.
one.one.one. 2067 IN NS dorthy.ns.cloudflare.com.
# dig -x 1.0.0.1
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 33563
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 9
;; QUESTION SECTION:
;1.0.0.1.in-addr.arpa. IN PTR
;; ANSWER SECTION:
1.0.0.1.in-addr.arpa. 1800 IN PTR one.one.one.one.
;; AUTHORITY SECTION:
0.0.1.in-addr.arpa. 86400 IN NS ns3.cloudflare.com.
0.0.1.in-addr.arpa. 86400 IN NS ns7.cloudflare.com.
</pre>
</body>
</html>