First of all, if you are going to change any DNS records, if you don’t know who controls your Domain Name’s records, then you may need to find out who your Domain Name is registered with.
To do that use WHOIS. e.g. https://mxtoolbox.com/SuperTool.aspx Find and search a domain using WHOIS in the Orange Button dropdown.
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Now In this unusual example above, you can see the Nameserver(s) are Godaddy’s but the Domain Name is actually registered with 123-reg not Godaddy. So that means the Website records and email records are being managed from and by Godaddy who in this case are the DNS provider for this Domain name. This can happen when email companies get involved in your domain name management as they can switch your records to their own DNS servers and Email management service provider e.g. email from Siteground or another company like Godaddy.
So, as per the example above, the registrar may not be who actually controls your Domain Name’s records, as the Nameservers (the records below)dictate who actually controls your DNS settings which include your A record, CNAME records and records like eMail (MX records) and others including TXT and SPF records.
In the WHOIS lookup with MXToolbox, If the top nameserver is not your registrar’s nameserver, and or this may manifest itself in the event that when you make changes to the domain name’s DNS records (DNS Settings) nothing actually changes when you use DNS Lookup to check the A record or CNAME record, then you must then check who the Nameservers are managed by, and therefore where your DNS records are being managed from.
To do that, you can either already see that from the WHOIS record using MXtoolbox, or you can check without WhoIS info and then instead use MX Toolbox’s SuperTool and click the DNS Check orange button.
https://mxtoolbox.com/SuperTool.aspx
Enter the root domain and select DNS Check from the Orange dropdown button
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