Micah Abrams wrote:
>
>
> 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
>
Not off hand. Some diligent googling might give you an answer. If you come
up with one, please let us know.
--
-Eric 'shubes'
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