On 21/01/15 12:50, Klaus Ethgen wrote:
> I go back to the list with that discussion...
>
> Am Mi den 21. Jan 2015 um 13:17 schrieb Jeremy Harris:
>> On 21/01/15 12:13, Klaus Ethgen wrote:
>>> Am Mi den 21. Jan 2015 um 13:09 schrieb Jeremy Harris:
>>>>>> How do they receive bounces?
>>>>>
>>>>> What do you mean, how do they receive bounces? Bounces are not different
>>>>> on that level. They are just regular mails.
>>>
>>>> If they have no MX or A, where am I to send a bounce to?
>>>
>>> To the sender address as you do with MX.
>
>> ... and this sender address has no MX, yes?
>
> Well why should it? It can but it is not mandatory. As it is for every
> other e-mail address.
>
> I think you are a bit confused from how mails are send at all.
>
> First there is DNS. In DNS you have usually an A record and/or an MX
> record. The mail server uses is to MX or A (in this order) to find the
> server to send mails to.
>
> That is all, MX is used for.
>
> Something completely different is a bounce or a bounce mail. A bounce is
> just a normal mail with two exceptions:
> 1. It is created by the mailserver
> 2. It has no sender address. (Envelope(!), nothing else is relevant for
> the server.
>
> However, as all other mails, it has an recipient address that is the
> envelope-from address of the original mail that causes that bounce.
Thank you, but I do know about email.
For me, operating as an MTA: if the envelope sender address has
a domain for which there is no MX or A record in DNS, then I cannot
send a bounce. For me, as the administrator of an MTA: if my MTA
cannot return a bounce to a sender then I cannot maintain overall
reliability of email, in the notification of error conditions.
Therefore I do do wish to take responsibility for such a message.
