Which DNS record identifies the e-mail servers within your domain?

• A. NS (Name Server)
• B. A (Address)
• C. MX (Mail Exchange)
• D. CNAME (Canonical Name)

Answer: (C)

An MX (Mail Exchange) record is the DNS entry that designates which servers are responsible for receiving email for a domain. When another mail server wants to deliver mail to someone at that domain, it queries DNS for the domain’s MX records and uses the server(s) listed, typically with a priority value to choose among multiple mail exchangers. The actual IP address of the mail server is usually found via an A (or AAAA) record for the hostname named in the MX record, but the key point is that MX identifies the destination mail servers, not general host addresses.

NS records point to the authoritative name servers for the zone, which is about who answers DNS queries for the domain, not where mail is received. A records map hostnames to IP addresses, which is part of locating a host but does not specify mail handling. CNAME records create an alias from one name to another, and aren’t used to designate mail recipients.