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Say you own a and you only want to use it to send and receive email via You don't want to provide any kind of website.

Can you set up the DNS records to include an "MX" record and no "A" record?

  • Is this enough for sending and receiving email to work?

  • Is this valid in terms of whatever standard defines these things?

Edit: To clarify, the mail server (terminology?) would not be hosted on or *

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up vote 22 down vote accepted

As long as the system pointed at by the MX record has an A record itself, then yes.

For example: can have a MX record pointing at As long as the name itself is resolvable to an IP address, this is a valid configuration for

Strictly speaking, should be an A record with the IP address in order to be RFC-compliant. But this A record will be in the domain, not in

Addressing your example, in order for to be a valid email address, needs to be configured to handle inbound mail for

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1 MUST be resolvable by A record so this answer is incorrect – Jim B Jan 6 '10 at 15:39
The mail-only domain does not require an A record if the MX record points to an A record in another domain. The question is only about the mail-only domain. – Ben Doom Jan 6 '10 at 15:53 will have an A record in the domain, not in the domain. – David Mackintosh Jan 6 '10 at 16:53

NO. The MX record points to a name. The names must be resolvable (via A record). The MX record should never point to a CNAME (RFC 1034 section 3.6.2, RFC 1912 section 2.4)

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True an MX records must point to an A record, but it doesn't have to point to one on the same domain. You could have the MX record for pointing to – Sam Jan 6 '10 at 15:08
that's not the question- MUST have an A record. It's required both by RFC and by definition – Jim B Jan 6 '10 at 15:38
Jim -- The question does not specity that the mx record point to the parent domeain. For example, I could point's MX record to Google mail, and have no A records in – Ben Doom Jan 6 '10 at 15:52
Yes, must have an A record, however he asked whether he needed an A record in, if the MX record for is pointing to (or etc) then he does not need an A record in the DNS Zone – Sam Jan 6 '10 at 15:57
You are correct, that's what the clarification says NOW but not when I answered the question. There was no mention of another domain. It then goes on to what the standard says. In addition being resolvable does not mean it's a A record. That being said, most mail servers will still submit mail to a CNAME; however, you can't be guaranteed of it. – Jim B Jan 6 '10 at 16:45

It is possible - if mail over IPv6 ONLY is desired - as the AAAA record pointed at by the MX record satisfies the address target requirement. Granted, IPv4-only hosts won't be able to contact such a setup, but that doesn't make it illegal under DNS rules.

Why were all the prior answers so IPv4-centric?

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