Mail not cooperating with Outlook

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Level 1

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Mail not cooperating with Outlook

Hello, hopefully I can get some help as I'm not too well versed in this area.

I was asked to get a mail server running for a class (students use Outlook). We already have Exchange running but did not want to go that route. We only want students to be able to send email on the local domain.

I changed mynetworks in main.cf to be empty. Assuming this will cause any mail being sent to a domain not hosted by my server to be rejected and to stop all relaying. I then created a test user "mailuser" and enabled mail. I tested using the Mail.app on 10.6.4 with success.

Here's where I have a problem. I tested this on a client running Outlook and I'm having authentication issues:

"The server responded: -ERR Plaintext authentication disallowed on non-secure (SSL/TLS) connections."

Email is being sent however.

Any help would be greatly appreciated.
Thank You

Mac OS X (10.6.4)

Posted on Sep 9, 2010 7:59 AM

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Answer 1

MrHoffman

Level 10

149,831 points

Sep 9, 2010 9:28 AM in response to mike.pinto

Ok, to confirm what your goal is and what you're up to...

You're looking for configuration assistance with Mac OS X Server mail, and specifically with the implementation of an email server configuration that disallows Microsoft Outlook clients (and presumably Mac OS X mail clients) from sending external email via Mac OS X Server mail system, correct?

If so, then you'll likely find the discussion [Restricting what users can send mail to off-site destinations|http://www.postfix.org/RESTRICTION CLASSREADME.html] interesting. It's a little arcane, but it should get you enough information and search keywords to get where you want.

You'll need perimeter firewall blocks regardless, as you'll find that some of your students are far more versed in this area, and inevitably sufficiently motivated, and it's trivial to bypass any server-implemented blocks via proxies or relays or direct connections to remote mail servers.

Probably a VLAN configuration to keep the students entirely separate from the trusted traffic, too.

If you want to enable plaintext (and that's not something I'd recommend doing in a "hostile" network) , set the disable plaintextauth knob appropriately in dovecot.conf (to "no") and restart dovecot. Google for details, etc.

And FWIW, Microsoft Outlook Express (or whatever Outlook Express is called these days) has traditionally been easier to deal with when working with servers other than Microsoft Exchange. The Outlook Express client was (is?) very different than Microsoft Outlook. And the other option is something like Thunderbird.

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Answer 2

mike.pinto Author

Level 1

0 points

Sep 9, 2010 10:07 AM in response to MrHoffman

Thank you for your assistance.

I did change the plaintext_auth to "no" earlier (figured it was a bad idea) but got the error: "The server responded: -ERR Unsupported authentication mechanism". If it's not one thing it's another.

Thanks again.

EDIT: I got it working but don't want plaintext. I'll take a look at the posted article, thanks.

Message was edited by: mike.pinto

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