DNS not working properly

[DennisMidjord]

Yesterday, everything was working fine, but when customers try to change theie DNS servers to ours, they get "Error: Domain doesn't exist on nameservers" or something along that line. This happens for all of the domains that has been tried transferred to us today.
I've checked, and all domains are existing in /etc/named.conf in all of the nameservers, and each DNS zone file on all of the servers have the same content.

What could the issue be?

 

[DennisMidjord]

It seems like our primary nameserver has stopped functioning.
When using nslookup to check for domains, we receive this:

C:\Users\denni>nslookup
Default Server: dns01.domain.dk
Address: 178.132.xxx.xx

> server ns5.example.dk
Default Server: ns5.example.dk
Addresses: 2a00:d880:5:a52::xxxx
81.4.xxx.xx

> example.dk
Server: ns5.example.dk
Addresses: 2a00:d880:5:a52::xxxx
81.4.xxx.xx

*** ns5.example.dk can't find example.dk: No response from server

But, every single DNS zone is present on the nameserver.

 

[Jcats]

Are you sure named is running?

service named status

Might also be a firewall issue blocking port 53

Are you positive your nameservers are registered at your registrar as well?

 

[DennisMidjord]

Hi,

named is running:

WARNING: key file (/etc/rndc.key) exists, but using default configuration file (/etc/rndc.conf)
version: 9.8.2rc1-RedHat-9.8.2-0.62.rc1.el6_9.2
CPUs found: 2
worker threads: 2
number of zones: 8044
debug level: 0
xfers running: 0
xfers deferred: 0
soa queries in progress: 0
query logging is OFF
recursive clients: 0/0/1000
tcp clients: 0/100
server is up and running
named (pid 723) is running...

We're able to telnet to and from port 53, so the port is open. It was working until yesterday and we've made 0 changes to anything.

 

[Jcats]

Yeah not sure, its not responding for me:

[root@office ~]# telnet dns01.domain.dk 53
Trying 178.132.xxx.xx...
^C

Just times out.

I want to blame a firewall. I would disable any/all firewalls including cphulk just in case.

If you are using CSF

# csf -x
# service iptables stop

 

[DennisMidjord]

Hi,

That is the default server that's used by my ISP. You should use ns5.example.dk.

 

[Infopro]

You should check your domains on a site like intodns.com for issues. I did, earlier, and again right now and things have updated on your domain but are still not proper. According to intodns.com. Seems like you've made some changes since I checked this morning.

That is the default server that's used by my ISP.

This one, now removed, shows as having no A record when checked.

 

[DennisMidjord]

Seems like you've made some changes since I checked this morning.

I tried making changes to 'Configure Address Records' for ns7.example.dk as this IP was changed a while ago. I simply updated the IP. This was done today.
It still don't make any sense how everything was working yesterday, but now they're not. Any idea what it could be?

 

[Infopro]

Two of your nameservers had incorrect IP addresses. DNS needs time to propagate. It might have seemed all was well yesterday and finally updated and broke today.

Best thing you can do is check everything and make sure it's correct. Then give it time to update. Make one change, wait again.

when customers try to change theie DNS servers to ours, they get "Error: Domain doesn't exist on nameservers" or something along that line.

That error probably means what I saw this morning. Your nameservers were using the wrong IPs, or something along that line.

 

[DennisMidjord]

Hi,

The IP was changed months ago. Nothing has been changed prior to the problems we have today.

 

[cPanelMichael]

Hello Dennis,

Feel free to open a support ticket using the link in my signature if you'd like us to take a closer look.

Thank you.

 

[DennisMidjord]

Hi,

I've submitted a ticket with ID 8569509.

 

[cPanelMichael]

Hello,

To update, it looks like this was a DNS cache issue unrelated to the cPanel configuration.

Thank you.

 

[DennisMidjord]

I'm actually not sure whether or not it was a cache issue. We've faced the issue a couple of times afterwards, and it seems that running a sync of all domains on just one specific name server (our secondary) seems to solve the issue. It seems to be lagging behind. We've tried comparing the zones manually on all 3 name servers, and there's no difference, but nothing works until we synchronize. I'm still trying to find out why.

 

[cPanelMichael]

Hello,

Feel free to reply to the existing support ticket if you require additional assistance from our side.

Thank you.