On 3/22/08 9:41 AM, "Eric Shubert" <[EMAIL PROTECTED]> wrote:
> Micah Abrams wrote:
>>
>>
>> On 3/22/08 8:24 AM, "Eric Shubert" <[EMAIL PROTECTED]> wrote:
>>
>>> Micah Abrams wrote:
>>>> List -
>>>>
>>>> I have been getting sporadic reports from users that people attempting
>>>> to send them msgs are receiving a bounce with following error:
>>>>
>>>> 511 sorry, no mailbox here by
>>>> that name (#5.1.1 - chkuser)>
>>>>
>>>> The users identified in the bounce msg definitely exist on the server
>>>> (no mis-spellings etc..) and these users are receiving mail otherwise.
>>>> I have checked the smtp logs and they report Œfound existing recipient¹
>>>> when the msg arrives. This particular server is also very low volume.
>>>> Any help/ideas would be much appreciated. This is a new install using
>>>> qmail-toaster-1.03-1.3.15.
>>>>
>>>> Thanks,
>>>>
>>>> Micah
>>> Does the send log give a clue?
>>
>> Thanks for the quick response. Unfortunately, there is nothing in the send
>> log for these msgs at that time... Also, on this particular msg (although I
>> don't think its always the case) the original sender sent the msg to 3
>> recipients on this server one of which was really did not exist. However
>> the bounce says that all 3 users do not exist (separate chkuser line in the
>> bounce for each user).
>>
>> Micah
>>
>
> I think you just explained what's happening.
>
> Mail servers handle multiple recipients to the same domain in different
> ways. For instance, qmail sends each message separately, which ensures that
> deliverable copies are delivered, at the expense of bandwidth. Some other
> servers (I don't know which ones off hand), in order to preserve bandwidth,
> send a single copy to all recipients in the same domain. When such a message
> arrives qmail splits it out to each recipient, but only after the message
> has been accepted (qmail cannot split it out beforehand). Since there's an
> invalid address in the message, qmail cannot receive it, and must bounce the
> entire message. It wouldn't be possible to deliver the valid ones and bounce
> just the invalid ones. That's why qmail does things the way it does - 1
> recipient per message. When a mail server sends a message with multiple
> recipients, this is what happens. It's 'normal' (albeit undesirable)
> behavior of some mail servers. In addition, it's practically impossible for
> the user to distinguish which address was invalid in this scenario.
>
> Any way to find out which MTA the sending server is running? (just curious)
>
> HTH
Thanks again for your timely and informative response. It goes a long way
in helping to diagnose the problem. I am not 100% sure about the sending
server, but I believe its some version exchange or at least running on
windows. Do you happen to know if this would be the expected behavior of an
exchange smtp server?
Thanks,
Micah
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