MX Kaydı

MX Record Structure

An MX record contains two fields: a priority (lower number = higher preference) and a mail exchanger hostname. The hostname must resolve to an A RecordA DNS record that maps a domain name to an IPv4 address (e.g., example.com -> 93.184.216.34). The most fundamental DNS record type for resolving domain names to IP addresses. or AAAA RecordA DNS record that maps a domain name to an IPv6 address. Named "AAAA" (quad-A) because an IPv6 address is four times the size of an IPv4 address. — it cannot be a CNAME RecordA DNS record that creates an alias from one domain name to another (e.g., www.example.com -> example.com). The alias inherits all DNS records of the target, but cannot coexist with other record types at the same name.. A typical setup might be:

example.com.  IN  MX  10  mail1.example.com.
example.com.  IN  MX  20  mail2.example.com.

When another mail server delivers email to [email protected], it queries for MX records, then connects via SMTP to the highest-priority (lowest number) server. If mail1.example.com is unreachable, it falls back to mail2.example.com. Multiple records with the same priority create a round-robin fallback.

MX Records and Email Security

Modern email authentication depends on records alongside MX. SPF (TXT record) lists authorized sending servers. DKIM (TXT record at a selector subdomain) holds the public key to verify message signatures. DMARC (TXT record at _dmarc.example.com) specifies policy for SPF/DKIM failures. None of these directly modify MX records, but all are queried during DNSDomain Name System. The hierarchical, distributed naming system that translates human-readable domain names (e.g., example.com) into IP addresses (e.g., 93.184.216.34). Often called the "phonebook of the internet." resolution as part of inbound mail verification.

Hosted Email Services

When organizations use email providers like Google Workspace, Microsoft 365, or Fastmail, the provider instructs them to replace their MX records with provider-controlled mail exchangers (e.g., aspmx.l.google.com). Inbound mail flows through the provider's infrastructure before reaching users. The domain owner retains control of MX records in their DNS but delegates the actual mail handling to the provider.

Use DNS Lookup to verify MX records and check record priority ordering for any domain.