Bytemark DNS servers inconsistent


#1

I am getting inconsistent results from Bytemark’s DNS servers for one host name - see below. The 91… address is wrong. Presumably the site owner misconfigured it a while ago, but the problem is persisting for me for 2 days (from logs). I am guessing they’ve cleared any issue quickly as the server handles mail for 140,000 domains. Has anybody else see a similar issue?

Separately, doesn’t anyone know how to restart the Debian resolver? I am trying to work around this by hardwiring /etc/hosts, but exim4 is still picking up the 91 address occasionally — seems to be going to the DNS servers.

Trying “mail3.eqx.gridhost.co.uk
Using domain server:
Name: 80.68.80.24
Address: 80.68.80.24#53
Aliases:

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4260
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;mail3.eqx.gridhost.co.uk. IN ANY

;; ANSWER SECTION:
mail3.eqx.gridhost.co.uk. 1732 IN A 95.142.156.6

Received 58 bytes from 80.68.80.24#53 in 0 ms

root@vaz:/run/systemd# host -a mail3.eqx.gridhost.co.uk 80.68.80.24
Trying “mail3.eqx.gridhost.co.uk
Using domain server:
Name: 80.68.80.24
Address: 80.68.80.24#53
Aliases:

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 27269
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;mail3.eqx.gridhost.co.uk. IN ANY

;; ANSWER SECTION:
mail3.eqx.gridhost.co.uk. 4106 IN A 91.208.99.11

Received 58 bytes from 80.68.80.24#53 in 1 ms


#2

If anyone from Bytemark is debugging, only the .24 DNS server is returning the wrong 91 address.


#3

Have you used bytemark’s DNS via symbiosis and removed one of the IP addresses?

I’ve had a situation before where having /srv/ with an IP in the config file, then removing it and putting the dns to another IP in the main /srv//config/dns/file has resulted in 2 IP’s being returned from the bytemark servers.


#4

Thanks @fenglish . This is probably the same underlying problem, but not my symptom exactly.

I forgot to mention that the hostname I am resolving is not mine, but someone else - a large hosting provider it seems.

I worked around it for now by removing .24 Bytemark DNS server from my /etc/resolv.conf .


#5

I should have spotted that - gridhost is TSO hosting I think.


#6

Hi @vvasilev, if you’re still seeing the problem, can log a ticket via support.bytemark.co.uk we should be able to take a more detailed look for you and get to the bottom of it.


#7

The problem has disappeared now as I guess some cache has expired. Also this is difficult to reproduce as the DNS queries appear to be randomly connecting to different instances.

I am still seeing an inconsistency that is persisting for a time longer than the entry expiry. However, this is not causing a problem for me any more and I don’t understand the DNS propagation intricacies to be certain it is an error. Here it is in case it is useful in future. Notice the TXT entry sometimes appears and sometimes doesn’t. And this happens for both IPv4 addresses of the DNS servers (I didn’t try the IPv6 addresses).

root@vaz:~# host -a mail3.eqx.gridhost.co.uk 80.68.80.25
Trying “mail3.eqx.gridhost.co.uk
Using domain server:
Name: 80.68.80.25
Address: 80.68.80.25#53
Aliases:

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 57358
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;mail3.eqx.gridhost.co.uk. IN ANY

;; ANSWER SECTION:
mail3.eqx.gridhost.co.uk. 3433 IN A 95.142.156.6

Received 58 bytes from 80.68.80.25#53 in 3 ms
root@vaz:~# host -a mail3.eqx.gridhost.co.uk 80.68.80.25
Trying “mail3.eqx.gridhost.co.uk
Using domain server:
Name: 80.68.80.25
Address: 80.68.80.25#53
Aliases:

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 62891
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;mail3.eqx.gridhost.co.uk. IN ANY

;; ANSWER SECTION:
mail3.eqx.gridhost.co.uk. 452 IN TXT “408ade2b-fc24-4401-9ebc-66a2325eaa2c”
mail3.eqx.gridhost.co.uk. 7052 IN A 95.142.156.6

Received 107 bytes from 80.68.80.25#53 in 2 ms
root@vaz:~# host -a mail3.eqx.gridhost.co.uk 80.68.80.24
Trying “mail3.eqx.gridhost.co.uk
Using domain server:
Name: 80.68.80.24
Address: 80.68.80.24#53
Aliases:

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 41007
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;mail3.eqx.gridhost.co.uk. IN ANY

;; ANSWER SECTION:
mail3.eqx.gridhost.co.uk. 6828 IN A 95.142.156.6
mail3.eqx.gridhost.co.uk. 228 IN TXT “408ade2b-fc24-4401-9ebc-66a2325eaa2c”

Received 107 bytes from 80.68.80.24#53 in 1 ms
root@vaz:~# host -a mail3.eqx.gridhost.co.uk 80.68.80.24
Trying “mail3.eqx.gridhost.co.uk
Using domain server:
Name: 80.68.80.24
Address: 80.68.80.24#53
Aliases:

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 23424
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;mail3.eqx.gridhost.co.uk. IN ANY

;; ANSWER SECTION:
mail3.eqx.gridhost.co.uk. 2637 IN A 95.142.156.6

Received 58 bytes from 80.68.80.24#53 in 1 ms