Barclays bank domain unresolvable only on some servers

Sun Jun 16 10:21:32 UTC 2019

On 16/06/19 09:59, Simon Forster wrote:
> A very quick check from an iPad showed the host resolving fine from a couple of different recursives. The local one:
> 
> Shared from ISC Dig for iOS
> ; <<>> DiG 9.13.3 <<>> @192.168.0.10 +dnssec +noqr +multiline federate-secure.glbaa.barclays.com
> ;; Got answer:
> ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 11792
> ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 9, ADDITIONAL: 12
> 
> ;; OPT PSEUDOSECTION:
> ; EDNS: version: 0, flags: do; 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
> 
> ;; AUTHORITY SECTION:
> barclays.com.           440 IN NS ns2.barcap.com.
> barclays.com.           440 IN NS a1-71.akam.net.
> barclays.com.           440 IN NS a18-65.akam.net.
> barclays.com.           440 IN NS ns3.barcap.com.
> barclays.com.           440 IN NS a10-66.akam.net.
> barclays.com.           440 IN NS a9-66.akam.net.
> barclays.com.           440 IN NS ns7.barcap.com.
> barclays.com.           440 IN NS a11-67.akam.net.
> barclays.com.           440 IN NS a12-64.akam.net.
> 
> ;; ADDITIONAL SECTION:
> ns2.barcap.com.         300 IN A 141.228.196.129
> ns3.barcap.com.         282 IN A 146.127.235.2
> ns7.barcap.com.         300 IN A 141.228.129.129
> a1-71.akam.net.         440 IN A 193.108.91.71
> a1-71.akam.net.         440 IN AAAA 2600:1401:2::47
> a9-66.akam.net.         440 IN A 184.85.248.66
> a9-66.akam.net.         440 IN AAAA 2a02:26f0:117::42
> a10-66.akam.net.        440 IN A 96.7.50.66
> a11-67.akam.net.        440 IN A 84.53.139.67
> a12-64.akam.net.        440 IN A 184.26.160.64
> a18-65.akam.net.        440 IN A 95.101.36.65
> 
> ;; Query time: 21 msec
> ;; SERVER: 192.168.0.10#53(192.168.0.10)
> ;; WHEN: Sun Jun 16 09:51:44 BST 2019
> ;; MSG SIZE  rcvd: 472
> 
> I guess proper troubleshooting would involve checking what each of the authoriatatives say. But it’s Sunday and the dogs need a walk.

Thank you for taking the time to look into it. It is possible that I 
don't understand the DNS protocol sufficiently, but shouldn't every 
subdomain level return a valid NS record?

dig @8.8.8.8 in NS glbaa.barclays.com

; <<>> DiG 9.11.2 <<>> @8.8.8.8 in NS glbaa.barclays.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 10986
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;glbaa.barclays.com.		IN	NS

;; Query time: 26 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Sun Jun 16 11:19:30 BST 2019
;; MSG SIZE  rcvd: 47

And yet Google's DNS does manage to solve the full
federate-secure.glbaa.barclays.com somehow

Is something amiss in the Barclays DNS config, and somehow Google 
servers manage to cope with it?

> 
> :-)
> 
> Simon
> 
> 
>> On 16 Jun 2019, at 09:43, 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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> 