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Old 09-21-2011, 04:47 PM   #1
gymiv@aol.com
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Location: linwood, KS
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5.1.2 unknown host error CentOS sendmail


I have an exchange 2007 server on my internal domain. In my dmz i have a linux box using sendmail. My webadmin has created a webpage that clients fill out and recieve an email with a download link. Sendmail sends the email through my exchange server. If i enter an internal address the email comes through fine. However if i try to send to ANY external email address i recieve this below. CIWEB2 is the linuxserver ciexch is exchange 2007 server. I need to allow these emails to be sent to outside clients. please help.

Delivery has failed to these recipients or distribution lists:

any@email.com
The recipient's e-mail address is invalid. Microsoft Exchange will not try to redeliver this message for you. Please check the recipient's e-mail address and try resending this message, or provide the following diagnostic text to your system administrator.

The following organization rejected your message: ciexch.cinet.instruments.com.






Diagnostic information for administrators:
Generating server: ciweb2.instruments.com

any@email.com
ciexch.cinet.instruments.com #<ciexch.cinet.instruments.com #5.1.2 SMTP; 550 Host unknown> #SMTP#

Original message headers:

Return-Path: <nobody@ciweb2.instruments.com>Received: from ciweb2.instruments.com (localhost [127.0.0.1]) by ciweb2.instruments.com (8.13.1/8.13.1) with ESMTP id p8K0lgAK003529 for <any@email.com>; Mon, 19 Sep 2011 19:47:42 -0500Received: (from nobody@localhost) by ciweb2.instruments.com (8.13.1/8.13.1/Submit) id p8K0lgLh003528; Mon, 19 Sep 2011 19:47:42 -0500Date: Mon, 19 Sep 2011 19:47:42 -0500Message-ID: <201109200047.p8K0lgLh003528@ciweb2.instruments.com>To: Jim Thomas <any@email.com>
--------------------------------------------------------------------------------
 
Old 09-22-2011, 10:11 AM   #2
TB0ne
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Quote:
Originally Posted by gymiv@aol.com View Post
I have an exchange 2007 server on my internal domain. In my dmz i have a linux box using sendmail. My webadmin has created a webpage that clients fill out and recieve an email with a download link. Sendmail sends the email through my exchange server. If i enter an internal address the email comes through fine. However if i try to send to ANY external email address i recieve this below. CIWEB2 is the linuxserver ciexch is exchange 2007 server. I need to allow these emails to be sent to outside clients. please help.
Well, not sure what we can help with. Seems as if the web page is acting correctly, and sendmail is sending the messages along to the next relay host in line, which is the Exchange server. The message is dying there. I know that some email servers are set up to only accept relays and/or send along messages, based on domains. Could be that your Exchange server is seeing your sendmail server as myfull.domain.com, when it is set to accept external messages only from domain.com. You could enable masquerading on the sendmail server, and change it there, or modify your Exchange rules to accept/shovel along emails.

Can't really help with Exchange or how to configure it, but that's the place I'd start, since it seems that's where the problem is.
 
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Old 09-23-2011, 01:29 PM   #3
gymiv@aol.com
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Thanks for the reply. I have tried all of that. You know its funny I have spoken with microsoft, posted in microsoft forums, i am currently speaking with support techs on the exchange side and the linux side. The microsoft people blame linux and linux people blame microsoft. The only people that have given me any hard evidence of the way things are happening are the exchange people i have spoken with. I walked into this setup so i have to deal with it. Why can't we get past all this blaming the other guy stuff and get down to some cold hard facts of why this is happening. Exchange and Linux are working like this in the real world, more so than i would like to admit. I wish everything was either microsoft or linux, my life as an admin would be a lot easier, but this is not the way the world works. We have narrowed the issue down to a configuration problem with sendmail. I am not completely new with sendmail but still have a hard time understanding it. The problem is in the sendmail config or dns resolution of something in the congig. Thanks for all your help i am going to contact a linux person regaurding this issue.
 
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Old 09-23-2011, 02:49 PM   #4
TB0ne
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Quote:
Originally Posted by gymiv@aol.com View Post
Thanks for the reply. I have tried all of that. You know its funny I have spoken with microsoft, posted in microsoft forums, i am currently speaking with support techs on the exchange side and the linux side. The microsoft people blame linux and linux people blame microsoft. The only people that have given me any hard evidence of the way things are happening are the exchange people i have spoken with. I walked into this setup so i have to deal with it. Why can't we get past all this blaming the other guy stuff and get down to some cold hard facts of why this is happening.
Excuse me, but I'm NOT blaming anyone, but I AM pointing to 'cold hard facts'. The facts (as you state them), are the data is coming from a web form correctly. It's being processed correctly, sent to sendmail, who (in turn) is sending it along to the Exchange server. The EXCHANGE server is not sending the mails out externally...but is processing them INTERNALLY.

That means that Linux/web/sendmail are working correctly, and relaying the mail to Exchange. From there, it's not working correctly...external mail isn't going out. Want to test it? Follow this:
http://james-lloyd.com/getting-sendm...-as-a-relay-2/
...and let your Sendmail server get out to the Internet. It'll shovel email along using Gmail's SMTP server...if you get emails then, that'll tell you alot. If not, you can run sendmail with VERY verbose logging and get alot more details/clues.
Quote:
Exchange and Linux are working like this in the real world, more so than i would like to admit. I wish everything was either microsoft or linux, my life as an admin would be a lot easier, but this is not the way the world works. We have narrowed the issue down to a configuration problem with sendmail. I am not completely new with sendmail but still have a hard time understanding it. The problem is in the sendmail config or dns resolution of something in the congig. Thanks for all your help i am going to contact a linux person regaurding this issue.
I've been an admin for a LOT of years, and getting things to work right is always a challenge, even in a homogeneous environment. Where it tends to get complicated is when you throw something proprietary into the mix.

Not sure how you narrowed it down...mind showing us what lead you to this conclusion?? Also, saying sendmail config or dns resolution is a VERY broad answer. Sendmail can be configured in LOTS of different ways, with lots of different options. Again, what do the logs on the Exchange server say?? As I mentioned in my first post, the domain name could be the problem, if it's being processed as server.domain.com, instead of domain.com. I've seen MANY mail configurations die, because the upstream server (Exchange in this case), is CONFIGURED to accept mail from domain.com, and will discard anything else, to keep from acting as an open relay. Again, this can either be dealt with by telling the Exchange server to accept mail from server.domain.com, or by configuring sendmail to use the masquerade option, and making everything show up as domain.com. Either fix will work, and it's not a fault/feature of either system that it works like that. It's just the way mail servers work. The logs can tell you why the external mails are dying, and can be further diagnosed from there.

Last edited by TB0ne; 09-23-2011 at 02:55 PM.
 
  


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