dnsops.gov DNSSEC Outage: 2018-06-18

Date: June 18, 2018

Overview

This page gives some details on the dnsops.gov DNSSEC outage on June 18, 2018. This domain suffered a 7-day DNSSEC outage that ended only a week prior, and for reasons unknown, the administrators redeployed the previous expired RRSIGs.

Timeline / DNSViz

DNSSEC Debugger

Unlike DNSViz, Verisign's DNSSEC Debugger doesn't archive results, so here's a screenshot of my web browser's output from June 18, 2018.

June 18, 2018 dnsops.gov 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 a dnsops.gov. @8.8.8.8

; <<>> DiG 9.4.2-P2 <<>> +dnssec a dnsops.gov. @8.8.8.8
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 29353
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags: do; udp: 512
;; QUESTION SECTION:
;dnsops.gov. IN A

;; Query time: 152 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Mon Jun 18 15:46:42 2018
;; MSG SIZE rcvd: 39

You have to disable DNSSEC to make DNS queries work:

$ dig +cd a dnsops.gov. @8.8.8.8

; <<>> DiG 9.4.2-P2 <<>> +cd a dnsops.gov. @8.8.8.8
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 65179
;; flags: qr rd ra cd; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;dnsops.gov. IN A

;; ANSWER SECTION:
dnsops.gov. 3599 IN A 129.6.100.203

;; Query time: 89 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Mon Jun 18 15:46:42 2018
;; MSG SIZE rcvd: 44

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: dnsops.gov.
[B] dnsops.gov. 3600 IN DNSKEY 256 3 8 ;{id = 65160 (zsk), size = 1024b}
dnsops.gov. 3600 IN DNSKEY 256 3 8 ;{id = 32229 (zsk), size = 1024b}
dnsops.gov. 3600 IN DNSKEY 257 3 8 ;{id = 32917 (ksk), size = 2048b}
dnsops.gov. 3600 IN DNSKEY 257 3 8 ;{id = 31580 (ksk), size = 2048b}
[B] dnsops.gov. 3600 IN A 129.6.100.203
;; Error: No keys with the keytag and algorithm from the RRSIG found
;;[S] self sig OK; [B] bogus; [T] trusted

Logfile examples