Barclays bank domain unresolvable only on some servers

[Sebastian Arcus]

On 16/06/19 12:37, Mark Andrews wrote:
> The servers for this zone are broken, they do not respond to queries with DNS
> COOKIE options present.  You can add server options to named.conf to work around
> this while Barclays fix their servers / firewalls.  Modern recursive servers are
> no longer working around broken servers that do not respond to queries.  See
> DNS flag day.  It looks like Barclays ignored the messages.
> 
> e.g.	server 157.83.102.245 { send-cookie false; };

Thank you for that - that is very helpful. Is there a named.conf option 
to leave the cookie support turned on, but for Bind to retry a query 
without cookies if it fails with cookies attached?



> 
> % dig federate-secure.glbaa.barclays.com @ns21.barclays.com +nocookie
> 
> ; <<>> DiG 9.15.0 <<>> federate-secure.glbaa.barclays.com @ns21.barclays.com +nocookie
> ;; global options: +cmd
> ;; Got answer:
> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 47102
> ;; flags: qr aa rd ad; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
> ;; WARNING: recursion requested but not available
> 
> ;; OPT PSEUDOSECTION:
> ; EDNS: version: 0, flags:; udp: 4096
> ;; QUESTION SECTION:
> ;federate-secure.glbaa.barclays.com. IN	A
> 
> ;; ANSWER SECTION:
> federate-secure.glbaa.barclays.com. 30 IN A	157.83.96.50
> 
> ;; Query time: 491 msec
> ;; SERVER: 157.83.102.245#53()
> ;; WHEN: Sun Jun 16 21:03:48 AEST 2019
> ;; MSG SIZE  rcvd: 79
> 
> % dig federate-secure.glbaa.barclays.com @ns21.barclays.com
> 
> ; <<>> DiG 9.15.0 <<>> federate-secure.glbaa.barclays.com @ns21.barclays.com
> ;; global options: +cmd
> ;; connection timed out; no servers could be reached
> %
> 
> 
>> On 16 Jun 2019, at 6:43 pm, Sebastian Arcus <s.arcus at open-t.co.uk> wrote:
>>
>> I have discovered Friday that the following domain used by Barclays bank in UK doesn't resolve properly - but only on some of my servers running Bind:
>>
>> federate-secure.glbaa.barclays.com
>>
>> It works on a server with v9.12.3, but it fails on a server with v9.11.0 and another one with v9.14.2. However, I don't think that the Bind version has anything to do with it. All servers are recursive servers.
>>
>> It also resolves fine if I point to Google dns servers.
>>
>> I've ran tests on the domain above using the MX Toolbox dns checker (mxtoolbox.com), and it fails with the following errors:
>>
>> 3  ns22.barclays.net  157.83.102.246  TIMED-OUT  518 ms  , rcode=NO_DATA
>> 3  ns21.barclays.com  157.83.102.245  TIMED-OUT  509 ms  , rcode=NO_DATA
>> 3  ns23.barclays.com  157.83.126.245  TIMED-OUT  504 ms  , rcode=NO_DATA
>> 3  ns24.barclays.net  157.83.126.246  TIMED-OUT  517 ms  , rcode=NO_DATA
>>
>> I've had to temporarily disable and bypass the local Bind instance on this server and point to Google dns, as users couldn't use online banking from Barclays because of the issue above.
>>
>> Does anybody have any idea why would it work on some servers and with Google dns, but not on other servers with Bind? Also, would someone mind trying to resolve the above domain at their end and see if they get the same errors please.
>>
>> Any suggestions appreciated. Thank you.
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