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Email configuration

Posted on 2008-10-06
Medium Priority
Last Modified: 2013-11-10
I am trying to do the following.  I have a Exchange 2007 Single Server setup as well as a Linux Postfix Email setup on a single server as well to.

The goal is to have all mail go to the Linux Postfix server - @company.com  then forward a copy to the Exchange Server (currently as company.local).  There will be some users who only want the Linux Postfix (as its our primary and they do not want to conform to Exchange at all) Otherwise I would not be asking here.  But the other half will be using Exchange as primary.  Currently we have it semi working for external email usage from both Exchange and Linux and when we send emails from Exchange it shows our @company.com address as the sender.

The problem we have run into is when we send email from the Exchange users to the Linux users they are not receiving the emails, they are delivered to their Exchange accounts only.  And that needs remedied, unfortunately I am not skilled enough to know how to do this.

The cycle needs to be  All Email is delivered to Linux, a copy is forwarded to Exchange.  Users using Exchange know that Linux emails will not sync obviously but they have no problem with policing that once a month or such.  Mainly doing this because some of us hate POP/IMAP email and the others hate Exchange... Go figure.  In the end if we cannot achieve this, the Exchange users will lose as this was a bet/test theory that both can coexist and both users benefit for what they want to use.

All help is appreciated.
Question by:omniumnetworking
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LVL 14

Expert Comment

ID: 22652553
The simple answer is that they can coexist but shouild not.  What you are trying to do is apease two groups by putting in multiple e-mail systems.  This will raise your support requirements (read more money) and be problematic at best.

I have been in very large companies that thought doing this was a good idea.  Many of thousands of dollars later a lightbulb came on and they finally threw out the competing e-mail systems.

So, here is your real solution.

If you are a UNIX shop, stay with Postfix.  Set up the Outlook clients to use POP and tell users that is the way it is.  Besides which, what is to hate about POP?  It is a very reliable e-mail protocol that has been around for a very long time.

If you want to be a Microsoft shop (or see some real benefit to Exchange...like shared calendars, task delegation, resource accounts, etc) set up Exchange throughout the organization and tell users that is the way it is.

I know the above may sound overly simplistic, but after 20 years in this game I am telling you that the path you are going down has been tried, and has failed.

OK, so now that I preambled with the correct technical and business solution, here are a couple of lousy patchs that will get you what you are asking for:

1)  Set up the Exchange server with a domain name that is not the same as your registered e-mail domain.
2)  Set up the Linux Postfix to accept relay from the Exchange server.
3)  Set up the Exchange server to relay all outgoing e-mail to PostFix (e.g. the Linux server should be the "Smart Host").  Be sure your masquerade domain is correct so the external world can reply back.
4)  Only Exchange users get accounts in AD.
5)  For non-Exchange users, set up AD contacts with the full correct e-mail address (these will be delivered to your Linux system)

If the above won't work because all users need AD accounts...

1)  Set up the Exchange server with a domain name that is not the same as your registered e-mail domain.
2)  Set up the Linux Postfix to accept relay from the Exchange server.
3)  Set up the Exchange server to relay all outgoing e-mail to PostFix (e.g. the Linux server should be the "Smart Host")  Be sure your masquerade domain is correct so the external world can reply back.
4)  Set up all user accounts that do not use Exchange to forward e-mail to their company account.

You may have to play around with settings and tweak to get the mail flow working exactly as you want it to.  As you have probably already surmized, the reason Exchange is not delivering e-mail back to Linux users is because the Exchange server "owns" the mail domain.  You have to set things up so that the Exchange server sees your company as a different organization -- so will send the e-mail out instead of delivering to it's internal mail store.

Author Comment

ID: 22653729
MDS-COS, yes I never would allow this to happen in a real organization.  This is literally between 6 users in the office.  3 Exchange 3 Linux.  Our problem with POP is the fact of PSTs and copies and nothing is synced like it is .  We much prefer using Outlook Anywhere and Active Sync with our Iphones.

One thing I kinda need a hold my hand lesson on is step 3 for your Exchange recommendation.  For 2007 Exchange where exactly I need to place these settings.

Thanks again once I have that I think we should be good and award the points.  I appreciated.
LVL 14

Expert Comment

ID: 22653935
A "real organization".  I like that!  Two e-mail servers in a 6 person office -- wow...

On Exchange 2007 you set up step 3 in your Send connector.  Here is a link that has screenshots and everything...  http://www.arrowmail.co.uk/howto/smrthost.aspx
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Author Comment

ID: 22654157
Yea I made those changes, but the issue I get now is for the Exchange users when they send email it shows from


a copy goes to both accounts like we want it.  But now Im trying to figure out how to get the masquerading in 2007 to work and still deliver mail to both.  If I add the email address on the user in Exchange as username@company.com mail only goes to Exchange between internal users (all 6 of us) isntead of both.  External users works just fine.  So kinda back to square one with it.

Mainly this is a test scenario/possible real environment item.  But as stated it really should be just one or the other.  In our case the other is a choice we dont want to live with.  Kinda the worker bees challenging the upper management hehe 3v3.

I know how to masquerade in 2003 but cant seem to get how its done in 2007 Exchange.
LVL 14

Expert Comment

ID: 22654251
Oh, just so you know.  There are some nice ways to deal with backing up and/or centralizing PST files rather than leaving them to flap in the wind on a users hard drive (just waiting for the inevitable day when something bad happens to the system).

Since you have your own Linux e-mail server, you actually can configure everything so that the e-mail stays on the server just like it would in Exchange.  Hey, what do you think we old farts did back before Microsoft?  I sure wasn't running around my UNIX and VAX centric networks trying to manage local mailbox stores on all all of my end-user systems!  To be fair to this statement, I also was not using Outlook as the e-mail client, but even with Outlook you can configure with IMAP or POP to overcome the limitations of Microsoft default settings (which are appropriate only for home users or small organizations that do not have a server).

Iphones are another issue.  Work quite nicely with Exchange.  I've never had reason to try to integrate PC Phones into a non-Exchange server environment.
LVL 14

Accepted Solution

mds-cos earned 2000 total points
ID: 22654482
Sorry.  I forgot.  In Exchange 2003 you set up the smart host and the masquerade in the same place (I actually should be careful here to use the correct Microsoft terminalogy -- you actually are setting the FQDN that you want your server to pretend to be.  The "masquerade" setting is for non-delivery message flow).

Back to the question, here are three article that discusses the situation in fair depth.  Sorry for resorting to links, but I have only done this with Exchange 2003 (for temporary migration purposes).  The links provide much better explanation of the 2007 equivilant process.  This used to be a very simple procedure, but somewhat more complex with 2007.

(here is an old question from Experts Exchange that is very relative as well)  http://www.experts-exchange.com/Software/Server_Software/Email_Servers/Exchange/Q_22617322.html

Perhaps a simpler solution...How comfortable are you with Postfix?  I think you can set it up to modify the domain before relaying to the outside world.


Author Comment

ID: 22654673
I got it all set.  Thank you for all your help!  Its working in harmony!  Now as I slowly gloat and reap the rewards hehe.

Author Closing Comment

ID: 31503503
Fast response time and very helpful!!!
LVL 14

Expert Comment

ID: 22655214
Fantastic!  Glad I could be of assistance.

Now you get to start reaping the support headachs ;-)  But at least it is on a scale of 6 rather than a scale of hundreds (last place I was at with multiple e-mail systems...due to politics...was 1000+ users.  Ugh.).

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