Where do my mailboxes sit?
Where your mail gets delivered is written in a single DNS record: the MX record. It answers the question even when nobody remembers who signed the contract.
What does that mean?
The MX record is the postal address of your domain. Whoever writes to you asks DNS
first: which server does this message belong to. The answer is a hostname like
mx00.ionos.de or example-com.mail.protection.outlook.com,
and the provider can be read off that name.
Often there are several MX records, each with a number in front. The lower number takes precedence. The others are fallbacks for when the first server happens to be unreachable.
The provider of the mailboxes does not have to be the same as the provider of the website, and neither has to be the place the domain is registered. Three contracts, three invoices, often three logins.
What can go wrong?
- There is no MX record at all. Some senders then try the domain's A record, most of them give up.
- The MX points at a hostname that no longer resolves itself. That looks like a valid record and is not one.
- After changing provider, the old MX is still sitting there alongside. Then mail lands sometimes here and sometimes there.
In short
The MX record says who takes delivery of your mail. Where you change it is said by the nameserver.
How do you fix it?
The MX record gets changed at whoever manages the DNS, not at the mail provider. Who that is stands in the result above. Your new provider will give you the values to put in there, and usually the matching SPF record along with them.
Questions that usually come up together:
