gsu.edu DNSSEC Outage: 2017-12-11

Date: December 11, 2017

Overview

This page gives some details on the gsu.edu (Georgia State University) DNSSEC outage on December 11, 2017.

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 December 11, 2017:

December 11, 2017 gsu.edu 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 gsu.edu. @8.8.8.8

; <<>> DiG 9.4.2-P2 <<>> +dnssec a gsu.edu. @8.8.8.8
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 26803
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1

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

;; Query time: 127 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Mon Dec 11 19:56:53 2017
;; MSG SIZE rcvd: 36

You have to disable DNSSEC to make DNS queries work:

$ dig +cd a gsu.edu. @8.8.8.8

; <<>> DiG 9.4.2-P2 <<>> +cd a gsu.edu. @8.8.8.8
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 37444
;; flags: qr rd ra cd; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;gsu.edu. IN A

;; ANSWER SECTION:
gsu.edu. 143 IN A 104.130.251.77

;; Query time: 7 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Mon Dec 11 19:56:53 2017
;; MSG SIZE rcvd: 41

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