.pt TLD DNSSEC Outage: 2018-07-12

Updated: July 13, 2018

Overview

This page gives some details on the pt (Portugal) TLD DNSSEC outage on July 12, 2018.

Timeline / DNSViz

Verisign's DNSSEC Debugger

Here's a screenshot I took on July 12, 2018, of the DNSSEC Debugger output:

July 12, 2018 .pt TLD DNSSEC outage

Google Public DNS: with and without DNSSEC

DNSSEC can be disabled in queries via the CD (checking disabled) bit. Let's compare DNS queries with and without DNSSEC. With DNSSEC, DNS queries result in SERVFAIL:

$ dig +dnssec ns pt. @8.8.8.8

; <<>> DiG 9.4.2-P2 <<>> +dnssec ns pt. @8.8.8.8
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 43879
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags: do; udp: 512
;; QUESTION SECTION:
;pt. IN NS

;; Query time: 28 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Thu Jul 12 09:30:30 2018
;; MSG SIZE rcvd: 31

You have to disable DNSSEC to make DNS queries work:

$ dig +cd ns pt. @8.8.8.8

; <<>> DiG 9.4.2-P2 <<>> +cd ns pt. @8.8.8.8
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 32107
;; flags: qr rd ra cd; QUERY: 1, ANSWER: 9, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;pt. IN NS

;; ANSWER SECTION:
pt. 7199 IN NS ns.dns.br.
pt. 7199 IN NS c.dns.pt.
pt. 7199 IN NS a.dns.pt.
pt. 7199 IN NS ns2.nic.fr.
pt. 7199 IN NS e.dns.pt.
pt. 7199 IN NS ns2.dns.pt.
pt. 7199 IN NS sns-pb.isc.org.
pt. 7199 IN NS d.dns.pt.
pt. 7199 IN NS b.dns.pt.

;; Query time: 31 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Thu Jul 12 09:30:30 2018
;; MSG SIZE rcvd: 197

drill trace

Since DNSSEC contains so much garbage, I put the complete drill trace into its own file with the relevant portion below (emphasis added):

;; Domain: pt.
[T] pt. 7200 IN DNSKEY 257 3 7 ;{id = 40995 (ksk), size = 2048b}
pt. 7200 IN DNSKEY 256 3 7 ;{id = 21299 (zsk), size = 1024b}
[B] Unable to verify denial of existence for pt. type A
;;[S] self sig OK; [B] bogus; [T] trusted

Logfile examples