Exchange delivery problems

[Jon Doe]

Hi everyone,

I'm having some major delivery with one of our vendors (which just happens
to be our largest). The problem doesnt seem to happen with any other
recipient.

The issue is that users at my company uses an application that sends mail
via SMTP. What's happening is that recipients on the other end would receive
multiple copies of the same message (sometimes up to 20 duplicates). In
trying to figure out what's happening, I eventually get a hold of the admin
at the other end, and was told they use (unix) SendMail together with
exchange. Apparently, being a large company, they get millions of e-mail a
day in spam, and Sendmail will occasionally send a "deferred status" to a
sender server. It looks like that in my case, when my server receives this
deferred status tag, it just keeps resending. So, when their mail server is
ready, it just sends all the copies.

I'm wondering first of all if anyone has run into this before... also, how
may I be able to stop my exchange (2003) server from resending messages
after a deferred status has been received? Also, anyone know where I may be
able to find a log of these (deferred tag) events on my server? My SMTP logs
don't show a deferred status as far as I can tell (unless I'm not looking in
the right place, or my SMTP logs aren't configured correctly). Would store
and forward help? If so, how would I configure that?

Any ideas would be greatly appreciated. Thanks!

[Erkan Aksoy]

Hello,

If understood correctly when your users send a mail to your vendor, its
getting you back with a deferral status. then your exchange server is
resending it in a defined time interval which is "First retry interval,
second ..." and can be found in Delivery tab of default SMTP virtual
server's properties. Its default value is about 10 mins if you didnt touched
there it should be still that. So if you change it and increase the time up
to 200 mins probably your problem will be solved. But this option can
produce some new problems like "long delivery time of mails". You may see
this in just a day.

And for your other questions i cant tell anything. Sorry for this.

Good luck.

Post by Jon Doe
Hi everyone,
I'm having some major delivery with one of our vendors (which just happens
to be our largest). The problem doesnt seem to happen with any other
recipient.
The issue is that users at my company uses an application that sends mail
via SMTP. What's happening is that recipients on the other end would
receive multiple copies of the same message (sometimes up to 20
duplicates). In trying to figure out what's happening, I eventually get a
hold of the admin at the other end, and was told they use (unix) SendMail
together with exchange. Apparently, being a large company, they get
millions of e-mail a day in spam, and Sendmail will occasionally send a
"deferred status" to a sender server. It looks like that in my case, when
my server receives this deferred status tag, it just keeps resending. So,
when their mail server is ready, it just sends all the copies.
I'm wondering first of all if anyone has run into this before... also, how
may I be able to stop my exchange (2003) server from resending messages
after a deferred status has been received? Also, anyone know where I may
be able to find a log of these (deferred tag) events on my server? My SMTP
logs don't show a deferred status as far as I can tell (unless I'm not
looking in the right place, or my SMTP logs aren't configured correctly).
Would store and forward help? If so, how would I configure that?
Any ideas would be greatly appreciated. Thanks!

[Jon Doe]

Yes, you did understand correctly. I was looking at the SMTP retry option,
but wondered if it was worth making a global setting change like that being
that I'm only having this problem with this vendor... I might do it as a
last resort though... but thanks for your response.

Anyone know about store and forward? The people at the other company
suggested that's the problem on my end. Anyone know what it does and how to
set it up? Thanks!

Post by Erkan Aksoy
Hello,
If understood correctly when your users send a mail to your vendor, its
getting you back with a deferral status. then your exchange server is
resending it in a defined time interval which is "First retry interval,
second ..." and can be found in Delivery tab of default SMTP virtual
server's properties. Its default value is about 10 mins if you didnt
touched there it should be still that. So if you change it and increase
the time up to 200 mins probably your problem will be solved. But this
option can produce some new problems like "long delivery time of mails".
You may see this in just a day.
And for your other questions i cant tell anything. Sorry for this.
Good luck.

Post by Jon Doe
Hi everyone,
I'm having some major delivery with one of our vendors (which just
happens to be our largest). The problem doesnt seem to happen with any
other recipient.
The issue is that users at my company uses an application that sends mail
via SMTP. What's happening is that recipients on the other end would
receive multiple copies of the same message (sometimes up to 20
duplicates). In trying to figure out what's happening, I eventually get a
hold of the admin at the other end, and was told they use (unix) SendMail
together with exchange. Apparently, being a large company, they get
millions of e-mail a day in spam, and Sendmail will occasionally send a
"deferred status" to a sender server. It looks like that in my case, when
my server receives this deferred status tag, it just keeps resending. So,
when their mail server is ready, it just sends all the copies.
I'm wondering first of all if anyone has run into this before... also,
how may I be able to stop my exchange (2003) server from resending
messages after a deferred status has been received? Also, anyone know
where I may be able to find a log of these (deferred tag) events on my
server? My SMTP logs don't show a deferred status as far as I can tell
(unless I'm not looking in the right place, or my SMTP logs aren't
configured correctly). Would store and forward help? If so, how would I
configure that?
Any ideas would be greatly appreciated. Thanks!

[Rich Matheisen [MVP]]

Post by Jon Doe
Yes, you did understand correctly. I was looking at the SMTP retry option,
but wondered if it was worth making a global setting change like that being
that I'm only having this problem with this vendor... I might do it as a
last resort though... but thanks for your response.
Anyone know about store and forward? The people at the other company
suggested that's the problem on my end.

When in doubt, point at the other guy. It may not be the right thng to
do, but it's makes the problem go away for a while. :)

Post by Jon Doe
Anyone know what it does and how to
set it up? Thanks!

SMTP *is* "store-and-forward".

Unless they're telling you that you've configured your server to wait
for ETRN or TURN or ATRN commands from them (which I doubt, becasue
they'd have to make changes at their end to accomodate that -- and
then they wouldn't have had to act confused about the whole thing).

[Rich Matheisen [MVP]]

Post by Jon Doe
I'm having some major delivery with one of our vendors (which just happens
to be our largest). The problem doesnt seem to happen with any other
recipient.
The issue is that users at my company uses an application that sends mail
via SMTP. What's happening is that recipients on the other end would receive
multiple copies of the same message (sometimes up to 20 duplicates). In
trying to figure out what's happening, I eventually get a hold of the admin
at the other end, and was told they use (unix) SendMail together with
exchange. Apparently, being a large company, they get millions of e-mail a
day in spam, and Sendmail will occasionally send a "deferred status" to a
sender server. It looks like that in my case, when my server receives this
deferred status tag, it just keeps resending. So, when their mail server is
ready, it just sends all the copies.

If that's what's happening then their Sendmail server is broken (which
isn't unusal).

If they send a 4xx status they shouldn't be keeping a copy of the
message. 4xx is a transient, retriable error and it's your servers
duty to resend the message for some period of time (the frequency and
duration of those retries is defined by you).

Post by Jon Doe
I'm wondering first of all if anyone has run into this before...

The only time I've seen behavior like that is when the entire message
is send and then the receiving server responds with a 2xx followed
immediately by a 4xx. If that's what you're seeing in your log files,
the receiving server b-r-o-k-e-n. It's up to them to fix their
problem.

Post by Jon Doe
also, how
may I be able to stop my exchange (2003) server from resending messages
after a deferred status has been received?

Why would you ever want to do that? It's not at all uncommon to get a
4xx status. If you returned the messages as undeliverable you'd be
spending an awful lot of time explaining why you did that.

Post by Jon Doe
Also, anyone know where I may be
able to find a log of these (deferred tag) events on my server? My SMTP logs
don't show a deferred status as far as I can tell (unless I'm not looking in
the right place, or my SMTP logs aren't configured correctly).

Look at the property page of the SMTP Virtual Server. Click the
"Properties" button at the bottom of the page, then click the
"Advanced" tab. Check ALL the boxes.

Post by Jon Doe
Would store
and forward help?

That's exactly the definition of SMTP. :)

Post by Jon Doe
If so, how would I configure that?
Any ideas would be greatly appreciated. Thanks!

[Jon Doe]

Thanks so much for your help!

Post by Rich Matheisen [MVP]

Post by Jon Doe
I'm having some major delivery with one of our vendors (which just happens
to be our largest). The problem doesnt seem to happen with any other
recipient.
The issue is that users at my company uses an application that sends mail
via SMTP. What's happening is that recipients on the other end would receive
multiple copies of the same message (sometimes up to 20 duplicates). In
trying to figure out what's happening, I eventually get a hold of the admin
at the other end, and was told they use (unix) SendMail together with
exchange. Apparently, being a large company, they get millions of e-mail a
day in spam, and Sendmail will occasionally send a "deferred status" to a
sender server. It looks like that in my case, when my server receives this
deferred status tag, it just keeps resending. So, when their mail server is
ready, it just sends all the copies.

If that's what's happening then their Sendmail server is broken (which
isn't unusal).
If they send a 4xx status they shouldn't be keeping a copy of the
message. 4xx is a transient, retriable error and it's your servers
duty to resend the message for some period of time (the frequency and
duration of those retries is defined by you).

Post by Jon Doe
I'm wondering first of all if anyone has run into this before...

The only time I've seen behavior like that is when the entire message
is send and then the receiving server responds with a 2xx followed
immediately by a 4xx. If that's what you're seeing in your log files,
the receiving server b-r-o-k-e-n. It's up to them to fix their
problem.

Post by Jon Doe
also, how
may I be able to stop my exchange (2003) server from resending messages
after a deferred status has been received?

Why would you ever want to do that? It's not at all uncommon to get a
4xx status. If you returned the messages as undeliverable you'd be
spending an awful lot of time explaining why you did that.

Post by Jon Doe
Also, anyone know where I may be
able to find a log of these (deferred tag) events on my server? My SMTP logs
don't show a deferred status as far as I can tell (unless I'm not looking in
the right place, or my SMTP logs aren't configured correctly).

Look at the property page of the SMTP Virtual Server. Click the
"Properties" button at the bottom of the page, then click the
"Advanced" tab. Check ALL the boxes.

Post by Jon Doe
Would store
and forward help?

That's exactly the definition of SMTP. :)

Post by Jon Doe
If so, how would I configure that?
Any ideas would be greatly appreciated. Thanks!

--
Rich Matheisen
MCSE+I, Exchange MVP
MS Exchange FAQ at http://www.swinc.com/resource/exch_faq.htm