What are MX records and which ones should be used for incoming filtering?

The Domain Name System (DNS) is like the telephone book of the Internet. Imagine you want to visit a website, such as www.yourdomain.com. Instead of knowing the IP address (a string of numbers that identifies a specific server on the Internet) of that website, you simply type in the human-friendly name (www.yourdomain.com) and the DNS system will help find the corresponding IP address.

DNS records consist of various fields that provide information about the domain. In addition to information about the name of the mail server for a particular domain, other information can also be transmitted.

• Name (<name>): The name of the entry specifies which domain or subdomain the entry applies to. This can be a complete domain such as yourdomain.com or a subdomain such as www.yourdomain.com.
• Time to Live (<ttl>) The TTL specifies how long the entry should be stored in the cache of the requesting server before it needs to be updated. This is to ensure that no outdated entries are used. If the end of the TTL is reached, the requesting server must query the DNS entry again from the name server. The TTL is always specified in seconds. For example, if you use a TTL of 3600 seconds, this means that the entry is stored in the cache for one hour before it needs to be updated.
• Class (<class>): The class of the entry specifies the scope of the entry. This entry is rather optional, as only the Internet is now considered. At the time when the resource records were introduced, there were still the two classes Hesiod (HS) and Chaos (CH). However, both networks are no longer operated today, which is why the field either remains empty or the abbreviation IN is always used.
• Priority (<priority>): Especially for larger projects, it can make sense to run several mail servers in parallel. In this way, you can ensure fail-safety and redundancy in order to maintain email communication at all times. The priority can be used to control the order in which the mail servers of a domain are to be addressed. This means that several servers can have the same priority and divide the incoming load between them or you can assign different priorities in order to specify a sequence. If the first server is not available or cannot handle the load, the server with the next highest priority is used.
• Type (<type>): The type of the entry specifies what kind of information the entry contains. In this case, we use the type MX.
• Data (<rdata>): The data of the entry contains the actual information associated with the entry. Depending on the type of record, the data can be an IP address, a host name or other information. For an MX record, the name of the mail server is always specified in the form of an FQDN (Fully Qualified Domain Name).

How is an MX record structured?

An MX record (Mail Exchange Record) is a special type of record in the DNS that is used to determine which server should receive emails for a particular domain. Let's say you have an email address like info@yourdomain.com. When someone sends an email to this address, the DNS needs to know which mail server to forward the email to. This is where the MX record comes into play. The structure of an MX record in a DNS zone is as follows:

yourdomain.com. IN MX 10 mail1.mailserver.com.

• yourdomain.com is the name of the domain to which the MX record applies.
• IN stands for Internet and indicates the scope of the record.
• MX is the type of record and indicates that it is a mail exchange record.
• 10 is the priority of the mail server. The lower the number, the higher the priority.
• mail.mailserver.com is the host name of the mail server that receives emails for the domain mailserver.com.
  
  

yourdomain.com.       IN MX 10 mail1.mailserver.com.
yourdomain.com.       IN MX 10 mail2.mailserver.com.
yourdomain.com.       IN MX 30 mail3.mailserver.com.

Which MX records do I have to use for EuropeanMX?

In order to use EuropeanMX for your incoming messages, it is mandatory to adjust the MX records in the DNS settings of your domain at your domain provider. Without changing the MX-records the use of the incoming filter is impossible! The following entries are required:

Global (recommended):

10 mx1.europeanmx.eu.
20 mx2.europeanmx.eu.
30 mx3.europeanmx.eu.
40 mx4.europeanmx.eu.

For redundancy reasons we recommend using our global data sets.

European Union:

10 eu.mx1.europeanmx.eu.
20 eu.mx2.europeanmx.eu.
30 eu.mx3.europeanmx.eu.
40 eu.mx4.europeanmx.eu.

The numbers 10 - 40 represent the respective priority. Please pay attention to the points at the end of the entries, which may be necessary depending on your provider.

These 4 entries should be the only ones of type MX, others may have to be deleted. It is best to make a note of the original MX entries so that you can restore them later. If you have problems to store the MX records, please contact your provider.

If you want to receive your messages only via servers within the EU, please contact our support.

Useful guides

Here we have compiled an overview of the most important hosting providers and their instructions:

• 1&1 (Only usable if you run your own mail server) 
• All-inkl
  
• strato
  
• United Domains
  
• alfahosting