> On 15 Mar 2023, at 16:49, Mark Andrews <ma...@isc.org> wrote:
> 
> 
> 
>> On 15 Mar 2023, at 15:42, Tim Maestas <tmaesta...@gmail.com> wrote:
>> 
>> Named should be sending queries with DO=1 and it should be getting back 
>> signed responses.  I suspect that you will need to run packet captures of 
>> the traffic to and from 162.140.15.100 and 162.140.254.200 port 53 from the 
>> nameserver.  Either signed responses will cease or DNSSEC requests will 
>> cease.  In either  case having the traffic around the transition should help 
>> to determine what is happening.
>> 
>> I've found that, after a fresh restart of named, if I query for 
>> "federalregister.gov A" I get a good AD response, and then subsequent 
>> queries for "www.federalregister.gov" are successful as well.  If however 
>> after a restart of named I begin with a query for www.federalregister.gov A 
>> then I get servfail, and subsequent queries for federealregister.gov 
>> servfail as well.  Here is the tcpdump from the 2nd (failed) case of an 
>> initial query for www.federalregister.gov:
>> 
>> 
>> reading from file dns.cap, link-type EN10MB (Ethernet), snapshot length 
>> 262144
>> 04:30:01.114458 IP (tos 0x0, ttl 64, id 35832, offset 0, flags [none], proto 
>> UDP (17), length 92)
>>    10.0.0.159.43263 > 162.140.254.200.53: [udp sum ok] 15013 [1au] A? 
>> www.federalregister.gov. ar: . OPT UDPsize=512 DO [COOKIE 352538a87bde87a5] 
>> (64)
>> 04:30:01.204863 IP (tos 0x0, ttl 229, id 4936, offset 0, flags [DF], proto 
>> UDP (17), length 80)
>>    162.140.254.200.53 > 10.0.0.159.43263: [udp sum ok] 15013*-| q: A? 
>> www.federalregister.gov. 3/0/1 . OPT UDPsize=4096 DO [|domain]
> 
> This is a malformed DNS response.  It looks like the server tried to send a 
> truncated response with an OPT record but failed to correctly update the 
> answer count field to zero.  
> 
> % dig www.federalregister.gov @162.140.15.100 +dnssec +bufsize=512 +ignore 
> +qr +norec
> 
> ; <<>> DiG 9.19.11-dev <<>> www. @162.140.15.100 +dnssec +bufsize=512 +ignore 
> +qr +norec
> ;; global options: +cmd
> ;; Sending:
> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 57919
> ;; flags: ad; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1
> 
> ;; OPT PSEUDOSECTION:
> ; EDNS: version: 0, flags: do; udp: 512
> ; COOKIE: 4a67cc813cfe03eb
> ;; QUESTION SECTION:
> ;www.federalregister.gov. IN A
> 
> ;; QUERY SIZE: 64
> 
> ;; Warning: Message parser reports malformed message packet.
> ;; Got answer:
> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 57919
> ;; flags: qr aa tc; QUERY: 1, ANSWER: 3, AUTHORITY: 0, ADDITIONAL: 1
> 
> ;; QUESTION SECTION:
> ;www.federalregister.gov. IN A
> 
> ;; ANSWER SECTION:
> . 32768 CLASS4096 OPT 
> ;; Query time: 271 msec
> ;; SERVER: 162.140.15.100#53(162.140.15.100) (UDP)
> ;; WHEN: Wed Mar 15 16:30:22 AEDT 2023
> ;; MSG SIZE  rcvd: 52


What I should have said about this is that this tells named that the server 
DOES NOT SUPPORT EDNS and hence DNSSEC as there is no OPT record in the 
ADDITIONAL section in a response where the port, query id and question match 
the request.

Now I have reported this via the web site but whether they take it seriously or 
not only time will tell.  It’s very hit and miss trying to report broken DNS 
servers.  The automated response is below.

Mark

Your request (42885) has been received and is being reviewed by our support 
staff.

Thank you for contacting the Office of the Federal Register (OFR).

The OFR publishes on behalf of more than 300 Federal entities and can only 
accept documents from Federal agencies. We have no involvement with, or control 
over, their policies or programs. The OFR is responsible for the accuracy of 
the content of the Federal Register and CFR, which must reflect what the agency 
submitted for publication in the Federal Register. Federal regulations do not 
permit OFR staff to provide assistance for requests asking the OFR to:
- evaluate or interpret material published in the Federal Register;
- provide legal analysis of material published in the Federal Register;
- explain or provide compliance guidance of material published in the Federal 
Register.
In addition, we are not permitted to perform research or make detailed 
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If you have a question about our office or one of our publications, we will 
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solicitations.
———
Mark Andrews
Mar 15, 2023, 1:47 AM EDT
 
Your DNS servers are sending malformed DNS responses. The server attempted to 
send a truncated DNS response but the answer count was NOT set to zero in the 
DNS header causing the OPT record to appear in the answer section rather that 
the additional section. You will need to contact your DNS vendor for a fix. 
This is causing DNS resolution failures in some circumstances. 

% dig www.federalregister.gov @162.140.15.100 +dnssec +bufsize=512 +ignore +qr 
+norec
; <<>> DiG 9.19.11-dev <<>> www.federalregister.gov @162.140.15.100 +dnssec 
+bufsize=512 +ignore +qr +norec
;; global options: +cmd
;; Sending:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 57844
;; flags: ad; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags: do; udp: 512
; COOKIE: ba894ad3a75d0394
;; QUESTION SECTION:
;www.federalregister.gov. IN A
;; QUERY SIZE: 64
;; Warning: Message parser reports malformed message packet.
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 57844
;; flags: qr aa tc; QUERY: 1, ANSWER: 3, AUTHORITY: 0, ADDITIONAL: 1
;; QUESTION SECTION:
;www.federalregister.gov. IN A
;; ANSWER SECTION:
. 32768 CLASS4096 OPT
;; Query time: 329 msec
;; SERVER: 162.140.15.100#53(162.140.15.100) (UDP)
;; WHEN: Wed Mar 15 16:41:53 AEDT 2023
;; MSG SIZE rcvd: 52
-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742              INTERNET: ma...@isc.org

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