9.18 BIND not iterated over all authoritative nameservers

[Mark Andrews]

Well if the bank is stupid enough to use NS records that point to nameservers that
do not exist on the internet then lookups FAIL.

% dig ns gtm.bankeasy.com
;; BADCOOKIE, retrying.

; <<>> DiG 9.19.18-dev <<>> ns gtm.bankeasy.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 48050
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
; COOKIE: dbef45feadd7b38501000000653c2cefd1f381fbb389e388 (good)
;; QUESTION SECTION:
;gtm.bankeasy.com. IN NS

;; ANSWER SECTION:
gtm.bankeasy.com. 0 IN NS bkx-bigip1-out.ffc.local.

;; Query time: 992 msec
;; SERVER: ::1#53(::1) (UDP)
;; WHEN: Sat Oct 28 08:34:39 AEDT 2023
;; MSG SIZE  rcvd: 111
%

Named now uses NS lookups to perform QNAME minimisation.  If one puts garbage in the NS
records then they should expect lookups to fail.  The NS records on both sides of a zone
cut are supposed to be IDENTICAL.  This is not a new requirement.  It has been this way
since the very beginning.

The bank needs to fix what they publish.

Mark

> On 28 Oct 2023, at 02:36, Michael Martinell via bind-users <bind-users at lists.isc.org> wrote:
> 
> Hello,
>  At this point I am hoping that somebody might have a workaround so that we can exclude domains from this behavior if they are broken on the far end. Does anybody have a workaround for this?
>  We are a small ISP and run BIND compiled from source. We currently run 9.16.x
> Every time we try to move forward with 9.18 customers start to complain that they are unable to reach certain websites.  This includes banks, universities, and other organizations.
>  I understand the goal is to get all DNS to RFC 6891, but from a practical standpoint, this isn’t working for customers, so we are prevented from upgrading either.
>  Related website:
> https://gitlab.isc.org/isc-projects/bind9/-/issues/3152
>  Our source code compile options:
> ./configure --with-gnu-ld --with-libxml2 --with-json-c --with-openssl=/usr/local/openssl && make && make install && ldconfig
>  When I do a dig against a server running 9.18 I get the following:
> dig @dns1.itctel.com view.bankeasy.com
> ; <<>> DiG 9.16.42 <<>> @dns1.itctel.com view.bankeasy.com
> ; (2 servers found)
> ;; global options: +cmd
> ;; Got answer:
> ;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 46906
> ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1
> ;; OPT PSEUDOSECTION:
> ; EDNS: version: 0, flags:; udp: 1232
> ; COOKIE: d8ce8161641fbfdf01000000653bcf9ad1fff99d24914278 (good)
> ;; QUESTION SECTION:
> ;view.bankeasy.com. IN A
> ;; Query time: 8 msec
> ;; SERVER: 2607:d600:1000:330:75:102:161:227#53(2607:d600:1000:330:75:102:161:227)
> ;; WHEN: Fri Oct 27 09:56:26 CDT 2023
> ;; MSG SIZE rcvd: 74
>   The same command resolves just fine when I run it against 9.16
> dig @dns2.itctel.com view.bankeasy.com
> ; <<>> DiG 9.16.42 <<>> @dns2.itctel.com view.bankeasy.com
> ; (2 servers found)
> ;; global options: +cmd
> ;; Got answer:
> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 30969
> ;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1
> ;; OPT PSEUDOSECTION:
> ; EDNS: version: 0, flags:; udp: 1232
> ; COOKIE: b0ec30c4ddfeacd301000000653bcf9ff140c249344242e0 (good)
> ;; QUESTION SECTION:
> ;view.bankeasy.com. IN A
> ;; ANSWER SECTION:
> view.bankeasy.com. 3133 IN CNAME view.gtm.bankeasy.com.
> view.gtm.bankeasy.com. 300 IN A 96.2.250.200
> ;; Query time: 11 msec
> ;; SERVER: 2607:d600:9000:330:75:102:160:227#53(2607:d600:9000:330:75:102:160:227)
> ;; WHEN: Fri Oct 27 09:56:31 CDT 2023
> ;; MSG SIZE rcvd: 125
> [root at brkr-dns2 bind-9.18.12]#
>  Michael Martinell
> Network/Broadband Technician
> 
> Interstate Telecommunications Coop., Inc.
> 312 4th Street West • Clear Lake, SD 57226
> Phone: (605) 874-8313
> michael.martinell at itccoop.com
> www.itc-web.com
> -- 
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-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742              INTERNET: marka at isc.org