Re: Client refusing incoming smtp messages

See below for answers to your questions, thank you.
--
Mark Anthony MCSE 2003


"Lanwench [MVP - Exchange]" wrote:

Masitpro_mcse <Masitpromcse@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
Yes, this is my EXCHANGE server that is causing this SMTP error
message.

Good. Then don't mention the client & SMTP server. :)

Another thing, there is not a Cisco Pix involved but there
is a Cisco 2600 in use provided by the ISP.

Whatever is answering on modns.moxa.com is behind a PIX.

{Have a Juniper Firewall implemented into the structure; could that be a
concern
with the problem I am having?}


What looks suspicious to
me is the modns.moxa.com domain

Well...it isn't a domain. modns is a host in the moxa.com domain. It's an A
(address) record.

{Checked my DNS and there is an A record for that host}


Is moxa.com your registered Internet domain?

{Yes, this is our registered domain}


Is 59.124.42.188 the *public* IP address you use on your own network?

{The publc IP address for the exchange server is 208.57.128.69 if that is what
you are inquiring about. The above address links the modns host name but don't
know what it is exactly for.}



since I not noticed this before
(maybe because all users are working and never came across this issue
before). This problem came to be when I just created a new user
account and sent test messages via the internet because sometimes
smtp errors occur because of typo mistakes and I checked that
already. Maybe should I delete the account and start over? You know
glitches are a part of life these days.... Let me know what's on your
minds.

No, this has nothing to do with your user account. Please answer my specific
questions (answer inline - it's easier to read/follow).


{Wonder why this is happening all of a sudden. Have not done any changes to
the
exchange server or anything else at that matter. Your assistance is very much
appreciated, Ms. Wench.








Masitpro_mcse <Masitpromcse@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
What I mean is client using Outlook 2003; sending out internet mai
via SMTP works fine.

OK; let's try this again, because this is important. If you are
opening an Exchange mailbox directly in Outlook (and are not using
an Internet mail account in Outlook), *Outlook* is not sending out
Internet mail. Nor is it receiving it. Instead, your Exchange server
is sending and receiving *all* mail, because it's got your internet
domain(s) in its recipient policies, and your registered internet
domain specifies your Exchange server in its MX records.


But when trying to RECEIVE internet email the
following SMTP error message occurs:

A message that you sent could not be delivered to one or more of its
recipients. This is a permanent error. The following address(es)
failed:

PeiJung.Lu@xxxxxxxx
SMTP error from remote mailer after RCPT
TO:<PeiJung.Lu@xxxxxxxx>: host modns.moxa.com [59.124.42.188]:
550 5.1.1 <PeiJung.Lu@xxxxxxxx>... User unknown


This is the NDR message received from the SENDER. The only way the
Outlook client can receive SMTP messages is when I send them thru
telnet. This was how I verified if there is a problem, seems like
SMTP Outlook client only receives internet email via telnet. This is
rather very quirky, so what went wrong?

Again, disregard the client - mentioning it is a bit of a red
herring. If Exchange is handling your mail, the client is not
relevant. Is Exchange

The sole MX record for moxa.com is modns.moxa.com (59.124.42.188).
If you are hosting your own mail directly on your Exchange server,
that must be your IP....right?

A telnet to modns.moxa.com on port 25 gives me a

220 ************************************** 200**2****0***00

This looks suspiciously like there's a Cisco Pix in use, as I
mentioned before, and you need to disable MailGuard on it before any
further troubleshooting can be done.

If you do not host your own mail in Exchange (e.g., if that is not
your public IP) then then this is not an Exchange-related issue at
all....if you're using a POP connector, or POP/IMAP anywhere, it's
important to mention that right off the bat.







Masitpro_mcse <Masitpromcse@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
Added new user account to AD/Exchange 2003 and verified smtp
address. Client is able to send out internet email messages

Meaning, using Outlook or OWA to connect directly to the Exchange
mailbox? No Internet Mail service on your mail client, right? .

but will not
accept incoming internet email.

Get following NDR message:

A message that you sent could not be delivered to one or more of
its recipients. This is a permanent error. The following
address(es) failed:

client@xxxxxxxxxx
SMTP error from remote mailer after RCPT
TO:<client@xxxxxxxxxx>: host modns.domain.com [59.124.42.188]:
550 5.1.1 <client@xxxxxxxxxx>... User unknown

When I telnet to that IP address on port 25, the banner looks like
you've got a PIX. If so, you need to disable Mailguard on it.

http://support.microsoft.com/kb/295725

This may or may not be the cause of your actual problem - your
description is a bit confusing.


The funny thing is I can send smtp messages via telnet and it is
received at the client mailbox. Always add or modify accounts and
I have not crossed this type of problem before; what to do next?

You'll need to provide more info, I think.

What's your real domain name? No need to hide it - it isn't a state
secret. :)




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