uscis.gov DNSSEC Outage: 2018-08-29

Date: August 29, 2018

Overview

This page gives some details on the uscis.gov DNSSEC outage on August 29, 2018.

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 August 29, 2018.

August 29, 2018 uscis.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 uscis.gov. @8.8.8.8

; <<>> DiG 9.4.2-P2 <<>> +dnssec a uscis.gov. @8.8.8.8
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 16734
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1

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

;; Query time: 16 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Wed Aug 29 01:02:29 2018
;; MSG SIZE rcvd: 38

You have to disable DNSSEC to make DNS queries work:

$ dig +cd a uscis.gov. @8.8.8.8

; <<>> DiG 9.4.2-P2 <<>> +cd a uscis.gov. @8.8.8.8
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 10561
;; flags: qr rd ra cd; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

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

;; ANSWER SECTION:
uscis.gov. 21599 IN A 173.252.133.166

;; Query time: 16 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Wed Aug 29 01:02:29 2018
;; MSG SIZE rcvd: 43

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: uscis.gov.
;; No DNSKEY record found for uscis.gov.
[U] uscis.gov. 28800 IN A 173.252.133.166
;;[S] self sig OK; [B] bogus; [T] trusted

Logfile examples