Resolved Unintended Additional A/MX DNS Records

[floh]

Server operating system version

Debian GNU/Linux 10 \n \l

Plesk version and microupdate number

Obsidian 18.0.54

Hello everybody,

I have configured the domain settings for a domain. I set up a single MX-Record as follows:

mydomain.com. 86400 IN MX 0 mydomain-com.mail.protection.outlook.com.

However, when I checked using dns-checker, I noticed two MX records from the Plesk server:

mydomain.com. 86400 IN MX 10 mail.mydomain.com.
mydomain.com. 86400 IN MX 0 mydomain-com.mail.protection.outlook.com.

I also noticed an A record that I didn't create. Similar to the additional MX record, this A record doesn't appear in the DNS settings for that domain:

mail.mydomain.com. 86400 IN A xx.xx.xx.xx

I am wondering why this is happening. The mail configuration for that domain is set to "Disabled for incoming mail," and I have double-checked the DNS configuration to ensure that I only created one record for outlook.com.

Do you have any idea why this might be occurring?

Best regards,
Floh

 

[Peter Debik]

Do you see the same issue when testing MX against mxtoolbox.com?

 

[floh]

Hi Peter,

No, I cannot test with mxtoolbox.com because I haven't changed the nameservers yet due to the ongoing issue we're discussing. Instead, I am using the following online tester:

Test DNS server records online (query A, AAAA, CNAME, MX, PTR, SPF, SRV, NS, TXT, or all available)

Query a DNS server on IP Addresses and Domain Names. Query DNS for MX, TXT, SPF, SRV, SOA and more.

manytools.org

This tool allows me to specify which nameserver to query for DNS records. This is the full result of that tool:

"MX" DNS records for mydomain.com, [DNS server xx.xx.xx.xx]:

mydomain.com. 86400 IN MX 0 mydomain-com.mail.protection.outlook.com.
mydomain.com. 86400 IN MX 10 mail.mydomain.com.
Additional records:

mail.mydomain.com. 86400 IN A xx.xx.xx.xx
ns1.mydomain.com. 86400 IN A xx.xx.xx.xx
ns2.mydomain.com. 86400 IN A xx.xx.xx.xx

(The masked IP address xx.xx.xx.xx are all same)

Best regards,
Floh

 

[Kaspar]

@floh that's a strange issue. If you run the following commands, are both MX record listed?

# plesk bin dns --info example.com

# plesk db "SELECT type, val, opt FROM dns_recs WHERE type = 'MX' AND host LIKE '%example.com%'"

(Replace example.com in these commands with your own domain name)

 

[floh]

Hi Kaspar, thank you for your quick reply.

The first plesk command looks good, but the database query is weird. The first line shouldn't exist. The second line is for a subdomain businesscard and there the dns and email-service are deactivated but shouldn't matter for mydomain.com, I think.

root@hosting:~# plesk bin dns --info mydomain.com | grep MX
mydomain.com. MX 0 mydomain-com.mail.protection.outlook.com.
root@hosting:~# plesk db "SELECT type, val, opt FROM dns_recs WHERE type = 'MX' AND host LIKE '%mydomain.com%'"
+------+------------------------------------------------+-----+
| type | val                                            | opt |
+------+------------------------------------------------+-----+
| MX   | mail.mydomain.com.                             | 10  |
| MX   | mail.businesscard.mydomain.com.                | 10  |
| MX   | mydomain-com.mail.protection.outlook.com.      | 0   |
+------+------------------------------------------------+-----+

I'd run following command:

plesk db "DELETE FROM dns_recs WHERE type = 'MX' AND host = 'mail.mydomain.com'"

But I don't want try that now because I don't know if it will break the plesk configuration if I manually modify the database.

Best regards
Floh

 

[Kaspar]

Try running plesk repair dns, see if that makes any difference. It should synchronize the DNS zones between the DNS server and the PSA database.

 

[floh]

Ok, I did it. I hope I didn't overwrite customers dns settings.

root@hosting:~# plesk repair dns

Checking the DNS configuration file ................................. [OK]

Checking the user DNS configuration file
 
  Restore the user DNS configuration file from the template? [Y/n]
    Restoring the user DNS configuration file ....................... [FIXED]

Restoring DNS server configuration
 
  Synchronize DNS zones with the DNS server? [Y/n]
    Synchronizing DNS zones with the DNS server ..................... [OK]

Error messages: 0; Warnings: 0; Errors resolved: 0

root@hosting:~# plesk db "SELECT type, val, opt FROM dns_recs WHERE type = 'MX' AND host LIKE '%mydomain.com%'"
+------+------------------------------------------------+-----+
| type | val                                            | opt |
+------+------------------------------------------------+-----+
| MX   | mail.mydomain.com.                             | 10  |
| MX   | mail.businesscard.mydomain.com.                | 10  |
| MX   | mydomain-com.mail.protection.outlook.com.      | 0   |
+------+------------------------------------------------+-----+

 

[Peter Debik]

Is mydomain.com also used as the hostname of the server?

 

[floh]

Nope, it has different FQDN.

 

[Peter Debik]

Could you please try to change the "opt" value that was previously 0 to 5 and then check again whether the record appears on the DNS page? I am asking, because this table is the source for what is displayed on the DNS page, and I don't see why it is not currently shown there as you say. The only explanation I can think of that the 0 in the opt field might cause that, but it is not very likely. Needs to be tested.

 

[floh]

Hi Peter, just to be sure you mean change the opt-value by MySQL-UPDATE command'?

 

[Peter Debik]

plesk db "UPDATE dns_recs SET opt = '5' WHERE type LIKE 'MX' AND val LIKE 'mydomain-com.mail.protection.outlook.com.' AND opt LIKE '0'"

 

[floh]

Hello Peter,

root@hosting:~# plesk db "UPDATE dns_recs SET opt = '5'  WHERE type = 'MX' AND val = 'mydomain-com.mail.protection.outlook.com.'"
root@hosting:~# plesk db "SELECT type, val, opt FROM dns_recs WHERE type = 'MX' AND host LIKE '%mydomain-com%'"
+------+------------------------------------------------+-----+
| type | val                                            | opt |
+------+------------------------------------------------+-----+
| MX   | mail.mydomain.com.                             | 10  |
| MX   | mail.businesscard.mydomain.com.                | 10  |
| MX   | mydomain-com.mail.protection.outlook.com.      | 5   |
+------+------------------------------------------------+-----+

On DNS-Page there the Value changed from 0 to 5 for mydomain-com.mail.protection.outlook.com. But mail.mydomain.com. and mail.businesscard.mydomain.com. still don't appear on the dns-page.

 

[Peter Debik]

It seems that I am having difficulties in understanding what is shown where. Probably that is due to the "mydomain.com" redacted content. I think you are simply looking into the wrong DNS record. For example, it is possible to add a subdomain "businesscard.mydomain.com" with the "add domain" button, so that it can indeed get its own DNS record page. Can you positively confirm that the subdomains like businesscard.mydomain.com do not exist in "Domains" or "Subscriptions"? If so, then I ask you to create a support ticket, because it is then unclear why these are present in the DNS table.

 

[floh]

businesscard.mydomain.com is a valid subdomain and there the dns-page is disabled as you can see in following screenshot:


But this subdomain doesn't matter for this issue for now.

This is the dns-page of mydomain.com (it's actually a .de domain but here I masked to mydomain.com due to privacy policy):


As you see, the order is by type and there is only one MX record with priority 5 (because we just changed from 0 to 5).

I hope the screenshots helps you. I can assure you that we are looking at the correct domain. I think I hit a bug that caused the inconsistency, will open a ticket now.

UPDATE: I just looked where I can create support-ticket, but I didn't find it. Where is it?

Best regards
Floh

 

[floh]

Found the ticket request page. Will fill in now.

 

[floh]

Unfortunately, I'm having difficulties with the tech support. They are testing with the current valid nameserver, which is not the Plesk server itself. I have already told them twice to perform the request directly at the Plesk server. Now they are asking me to contact my domain registrar or hosting provider. :/ I will explain it to them for the third time...

 

[Peter Debik]

businesscard.mydomain.com is a valid subdomain and there the dns-page is disabled as you can see in following screenshot:
View attachment 23887

But this subdomain doesn't matter for this issue for now.

It does matter, that is the whole point of my post above, that if the subdomain is operated as a separate domain, it also has its own DNS settings. So your additional MX record that you are seeing in the database but are not seeing in your main domain DNS page comes from the businesscard.<domain> configuration.

 

[floh]

Hello Peter, thank you for clarifying. As you can see in the screenshot, the DNS service is disabled for the business subdomain. Or did I overlook/misunderstand anything? Should I enable the dns service for that subdomain and see if there is MX record and delete it before disable it again?

(In the meantime, the tech support now gladly understands my issue. )

 

[floh]

With the help from Plesk support everything is fixed now after he repaired my dns database. Also following command is useful if you want find out which domain contain a record:

plesk db "SELECT host, dns_zone_id, type, val, opt FROM dns_recs WHERE type = 'MX' and host LIKE '%example.com%'"

Now this thread is resolved, thank you all!

Best regards!
Floh