After some experimentation I think I can compress this problem down to one

Is it possible for an OpenSMTPD host to process email addressed to two
different host names, both of which resolve to the same address?

When I set "mailname," any mail sent to that name works fine. Mail
addressed to the alternate host name loops.

I thought the "virtual" keyword would be for this purpose, but I've had no
luck with it.


On Tue, Feb 9, 2016 at 10:44 AM, Michael Burk <> wrote:

> Thanks Craig for the reply.
> I changed the CNAME to an A record as you suggested. Sadly, it still loops
> when I send the email to the "alternate" name. It seems that OpenSMTPD
> doesn't realize that the two names are the same server.
> I should mention that the whole reason we have an alias is that I have two
> servers setup as mail servers, and the alias gives us an easy way to switch
> hosts if one goes down (all mail is addressed to the alias). Also, I have
> no MX records. I don't know if I should, but Sendmail has always worked
> without it.
> On Tue, Feb 9, 2016 at 4:42 AM, Craig Skinner <>
> wrote:
>> Hi Michael,
>> On 2016-02-08 Mon 16:49 PM |, Michael Burk wrote:
>> >
>> > If I send a message to the server's CNAME, it goes into a loop which is
>> > eventually detected and shut down:
>> >
>> Try switching from DNS CNAMES to DNS A records:
>> RFC2181 has:
>> "10.3. MX and NS records
>> The domain name used as the value of a NS resource record, or part of
>> the value of a MX resource record must not be an alias.  Not only is the
>> specification clear on this point, but using an alias in either of these
>> positions neither works as well as might be hoped, nor well fulfills the
>> ambition that may have led to this approach.  This domain name must have
>> as its value one or more address records.  Currently those will be A
>> records, however in the future other record types giving addressing
>> information may be acceptable.  It can also have other RRs,
>> but never a CNAME RR. ...."
>> --
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