[qmailtoaster] 511 sorry, no mailbox here by that name (#5.1.1 - chkuser)

[Micah Abrams]

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

[Eric Shubert]

Post by Micah Abrams
List -
I have been getting sporadic reports from users that people attempting
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 ‘found existing recipient’
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?

[Micah Abrams]

Post by Eric Shubert

Post by Micah Abrams
List -
I have been getting sporadic reports from users that people attempting
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




---------------------------------------------------------------------
QmailToaster hosted by: VR Hosted <http://www.vr.org>

[Eric Shubert]

Post by Micah Abrams

Post by Eric Shubert

Post by Micah Abrams
List -
I have been getting sporadic reports from users that people attempting
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

[Micah Abrams]

Post by Eric Shubert

Post by Micah Abrams

Post by Eric Shubert

Post by Micah Abrams
List -
I have been getting sporadic reports from users that people attempting
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




---------------------------------------------------------------------
QmailToaster hosted by: VR Hosted <http://www.vr.org>

[Eric Shubert]

Post by Micah Abrams

Post by Eric Shubert

Post by Micah Abrams

Post by Eric Shubert

Post by Micah Abrams
List -
I have been getting sporadic reports from users that people attempting
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.

[Micah Abrams]

Post by Eric Shubert

Post by Micah Abrams

Post by Eric Shubert

Post by Micah Abrams

Post by Eric Shubert

Post by Micah Abrams
List -
I have been getting sporadic reports from users that people attempting
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.

I didn't have much luck on google so I setup an exchange account and tried
it out. I sent a msg with one valid and one invalid recipient to my
qmail-toaster and sure enough it generated a bounce for both addresses with
the chkuser 511 error msg.


Thanks again for all the help -

Micah




---------------------------------------------------------------------
QmailToaster hosted by: VR Hosted <http://www.vr.org>

[Eric Shubert]

Post by Micah Abrams

Post by Eric Shubert

Post by Micah Abrams

Post by Eric Shubert

Post by Micah Abrams

Post by Eric Shubert

Post by Micah Abrams
List -
I have been getting sporadic reports from users that people attempting
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.

I didn't have much luck on google so I setup an exchange account and tried
it out. I sent a msg with one valid and one invalid recipient to my
qmail-toaster and sure enough it generated a bounce for both addresses with
the chkuser 511 error msg.
Thanks again for all the help -
Micah

Thanks Micah, that's nice to know. This would make a nice FAQ for someone
to add to the wiki (not so much a *Frequently* asked question, but a good
thing to know).

Makes me wonder if there's a way to tailor Exchange to behave like qmail in
order to avoid this problem. Good reason to not use Exchange server if there
isn't. ;)