IMAP Mail Server that works with Active Directory? Exchange

emailexchange-2010windows-server-2008

I have a small AD Domain running on Win2008 R2. I have several e-Mail accounts with a Provider.

What I would like is to have a Mail Server in my Domain that picks up the mail from my Provider (POP3), stores them locally and makes them accessible to a domain user through IMAP (so that I can access it on multiple machines). Sending mail should go from my Client to my Server and them to the providers SMTP.

I'd like to integrate with my exising Active Directory users, so that my IMAP Usernames/Password are the same always as the AD User. Also, it should behave "friendly" towards the Windows Backup, so no "can't backup as files are in use"

Can Exchange 2010 do that? Or is there another Mail Server that does that? I don't need fancy stuff like public folders and the like.

Best Answer

It looks as if hMailServer (Official site / Wikipedia page) would serve your needs perfectly.

It uses a database to store its own configuration and mail index data. This could be backed up using the standard tools provided by your DB engine of choice.

Mail data, i.e. the actual email messages, is stored as raw MIME format, i.e. plain text and you should have no issues making backups of that.

It has AD integration so that your users don't need to remember yet another password.

Related Solutions

Fetch all Mail from an IMAP server with Postfix to distribute on local IMAP server

Here the proposed mail-flow-diagram for your case.

External mail server
   |        ▲
   |        |
  POP3     SMTP
   |        |
   ▼        |
Local mail server

First, you need setup working local mail server with postfix and dovecot. The important parameter for postfix is never list your local domain in relay_domains. You can use virtual_mailbox_domains or mydestination for local domain.

Second, you need to populate/synchronize the user from external mail server to local. So, external mail server has the valid recipient list for receiving email and local mail server has user database for authentication and management.

For outgoing email flow, just setup SMTP submission service with SASL. Then setup relayhost in postfix to your external mail server. You should also setup postfix SMTP client with single username or other method. It would depends on your provider mail server.

For incoming email flow, you should use cron/other daemon method to periodically check INBOX in external mail server, download new messages via POP3 (don't forget to delete it after download) and put it in the right mailbox. Fetchmail will be suitable for this task.

HA mail server configuration

You would need to cluster your Dovecot service. This is commonly done using a highly-available shared storage (which can be a distributed file system like GlusterFS / RedHat GFS2), see the Dovecot Wiki for details.

It also seems possible to use the dsync mailbox replication engine for keeping your instances in sync without the need for shared storage. A design draft dealing with the details of such an implementation has been published on the Dovecot blog. Make sure to use the latest 2.2 release of DoveCot if you take this route.

The SMTP service for incoming mail would not need clustering as such - the protocol is designed for fault-tolerant implementations without a single point of failure. You simply can set up two independent Postfix instances delivering to your Dovecot cluster and provide MX records pointing to each of them.

To have users connect seamlessly to your SMTP and IMAP services during an outage, consider providing a virtual IP address using a cluster resource manager service similar to Pacemaker which would be set up to direct users to the functioning server immediately and any outages would go truly unnoticed. If you cannot spare another IPv4 address for the use as a virtual IP, just setting up your both servers' IP addresses as A records for a single label in the DNS would do the job too, but clients might notice inconsistent behavior or prolonged connection times while trying to connect to an unavailable or malfunctioning server.

Best Answer

Related Solutions

Fetch all Mail from an IMAP server with Postfix to distribute on local IMAP server

HA mail server configuration

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