I would like to know who here uses a linux email server such as postfix in a production environment? If you are using it what type of hardware do you have it on, how many clients is it serving, how do you provide web access? I'm a windows guy that uses exchange but I've been reading up on freebsd. I like exchange but I also would like to learn about other mail servers such as postfix. My last concern is do they have any virus scanning programs for linux mail servers.

Not an email admin but sendmail is pretty popular in the corporate environment.

I use postfix running on top of debian in a production enviroment. Relays about 100k emails every morning from our web apps. As for hardware, dual p3 1.1ghz, 1gb ram, and 60GB in a raid 5 scsi configuration. For antivirus scanning, I use amavis + clamav which works great. If you are looking for an opensource groupware replacement for exchange, there isn't any that can compete with exchage yet.

I'm not looking for anything that can compete with exchange although one day I'm sure it will be something out there. I'm manily interested in learning how to deploy a fast robust mail server. Besides a lot of companies use web portals for collabration. I consult every now and than and everyone can't afford exchange small business owners mouth drop when they see how much it cost hell some medium companies have a problem with how much exchange cost. So I'm new to all this stuff I'm just trying to educate myself so I can provide options. So do what do you think is best for me to start out this test server on freebsd or redhat enterprise linux?

Whichever os you know better. I'd image getting a basic smtp server setup on redhat would probably be easier and quicker then freebsd. Performance wise, I doubt there would be any difference between linux and freebsd for smtp.

I have been running QMail for over 2 years now. They had a reward for anyone who found a security hole (in QMail itself, not SMTP vulnerabilities or anything) that was never claimed. It's a little awkward sometimes, but I've been extremely happy with it. I help support the Qmail-Toaster project (qmailtoaster.com) and have to say that it's a nice, easy to setup, secure, and feature-rich package.
My 2 cents.

There is a good proprietary solution though - Check out Scalix. If all you need is email (unlimited users) or if you have 25 users or fewer, then you can run it for free, albeit without support.

I've been doing a bit of reading about it and started doing some testing on a staging box over the last few days and it's quite good so far. The only thing that we'd be losing if we migrate is the task list function, but since we've been using SugarCRM for task assignment and management losing that functionality is of little consequence.

Pros of Scalix vs. Exchange
- Community Edition provides FREE unlimited email users, FREE up to 25 groupware users
- Licenses are cheaper than Exchange licensing (ESPECIALLY when you take TCO into account: CAL + OS + application + client licenses PLUS "scheduled downtime" for maintenance, which is downtime that Microsoft never includes in their feature and TCO comparisons)
- Maintenance and integrity check tasks can be done LIVE (ZERO downtime is achievable)
- Backups are more simple than Exchange and can be done live (to be fair, Exchange backups can be done live) and are EASILY automatable
- Java client (TRUE cross-platform web client)
- Outlook connector (users who prefer Outlook can use Outlook)
- Evolution connector is on its way (it's not going to be a fugly hack like Novell's Ximian Exchange connector for Evolution)
- Java administration interface (Admin the server via a web browser)
- Full command line interface for admin and maintenance tasks
- Full compatibility with ClamAV as well as commercial gateway antivirus solutions
- Full compatibility with Spamassassin
- Integrates with Sendmail

http://www.scalix.com/products/platform.html

Note: I am not affiliated with Scalix in any way. It just looks like a great solution and it's very likely what I am migrating our company to in 1Q2006.

Why am I finally dumping Exchange for Scalix? I got totally fed up with Microsoft Exchange because we run commercial antivirus and spam filters and the spam filters went nuts a few weeks ago and deleted a few hundred emails. When I restored the backup, of course Exchange replayed all the transactions done since the last full backup, and you know what that means. That's right: It replayed the very same transactions I wanted to recover from. It went and deleted all of the legitimate emails that the spam filters falsely detected as spam (they were mainly zip files and word documents). Not only that, but the antivirus solution is terribly annoying in that when it runs full scans it sends notifications about unscannable encrypted files (we encrypt code attachments when sending work to clients, of course) even though I explicitly disabled that option, so every day when the full scans are run, we each receive many, many notifications that I have filtered directly to the bit bucket.

With ClamAV, Spamassassin, and Sendmail, Postfix or Scalix, the system will work the way I tell it to work, and if I find that Sendmail, Spamassassin or ClamAV are sending me notifications I don't want, I can RTFM and find out how to disable them, or if there is no way to disable I know we can dig into the source and add options to disable the notifications. Not only that, but I know that if one DNS blacklist shuts down because of a DDoS, I can just point Spamassassin at a different blacklist and don't have to worry that it's a binary-only filter that I cannot fix (hex editing aside) and I won't get brushed off by a vendor who tells me that if I want support for different blacklists, because it's hardcoded, I need to pay hundreds more for the enterprise version of the software because they discontinued the single-purpose DNS blacklist version.

Lastly, I hit a bug with Microsoft Exchange for which the Kb article indicates the only solution is reformat, reinstall, and restore from backup. Sorry, if I am going to have to do that, Microsoft just bumped up my schedule for migrating AWAY from their expensive proprietary solution to an alternative, which will be a combination of reasonably-priced proprietary solution and open source solutions. In the meantime, I will just manually work around the bug until Scalix releases their next version. This way, I don't have to buy the OS PLUS the server app plus the CALs PLUS the client software license PLUS the antivirus filter PLUS the spam filter PLUS the blacklist filter. I originally felt like I was throwing thousands away when I first considered dumping Exchange, but now I feel very differently about it. Now all I need to pay for is the per-seat licenses for Scalix - if we outgrow the community edition, and support if we need it. I don't need to buy all of the other obligatory crap which SHOULD come with the server by default. Heck, with what one pays for Microsoft Exchange, you should receive a free thick client for every CAL you buy.

So now you have what is actually the short version (believe it or not) of why I am so much against Microsoft Exchange.