Domain of sender address ... does not exist

[Philip A. Prindeville]

On 12/11/2009 03:20 PM, Greg Woods wrote:
> On Fri, 2009-12-11 at 18:02 -0500, Tony Nelson wrote:
>   
>> there is no requirement that a 
>> domain have an A record to exchange mail
>>     
> True, but there are plenty of mail servers (including sourceforge.net)
> that verify DNS information by back connecting. The domain therefore has
> to either have an A record, or an MX record pointing to a server that
> does have an A record, and the server the MX points to (or A if no MX)
> must be reachable on the SMTP port. We have found this out because we
> modify all MX records to point to our gateway, and we've had people send
> mail out from machines we weren't told were mail originators (and
> therefore they have no MX), and since the SMTP servers on these machines
> are not reachable from outside, mail servers like sourceforge.net refuse
> to accept mail from these hosts. So it is possible to have your outgoing
> mail rejected due to DNS inconsistencies.
>
> --Greg
>
>   

Well, I did some digging.

One instance where this happens is the following.

If I send this to my own "user at fedoroproject.org" account, from my account here (which is were it gets forwarded back to anyway), then I see this behavior.

If I sent this to the same account from a 3rd party server (gmail, etc) then it works fine.

Very, very odd.