E-Mail Server Setup Advice?

dhammala asks: "I am responsible for setting up and maintaining a mail server for small web-hosting type business. We currently host about 75 domains, around 100 mailboxes and due to the efforts of our sales team, we are wanting to get ready for some great increases in those numbers. I am worried about my current configuration and ease of administration. More importantly (well, at least to the customers) is email deliverability -- it seems that messages delivered to some big players are being marked as SPAM or disappearing altogether. I am asking the Slashdot community for it's insight and advise on 1) if my current choice of software/configuration is a good match for this situation and 2) if there any additional measures I might take to ensure email deliverability?" "Here is an overview of our current setup:

• We lease servers at ev1servers.net.
• The servers are running RHEL ES3.
• We chose to use Postfix and have it configured to support virtual users and domains mapped in MySQL tables. The reference I used to configure this setup is located here. We initially chose Postfix over qmail because it was open and over sendmail because the config files are actually readable.
• I have added in SQLGrey grey-listing for Postfix to provide a simple level of SPAM detection for our users. We are not wanting to deal with the customer service and higher box loads of mail scanning at this time. We might choose to use a 3rd party vendor to do this as needed.
• Messages are delivered locally via maildrop in maildir format.
• Courier IMAP is running to support both IMAP and POP access to the mailboxes.
• Postfix Admin was setup for easy mailbox administration.

For deliverabilty, I have/am taking the following steps:

• I have verified that our reverse IP records are correct
• I have created SPF records for all of the domains
• I have verified that our server is not listed in any blacklists (great scanner at dnsstuff.com)
• I have started to install DomainKeys for Postfix

In doing all of that, I have found that our IP is listed in the BlarsBL. Do I need to be concerned about this rogue list? The IP was there before I even began to setup the box.

I have not yet been able to get DomainKeys to work with Postfix. It was during my configuration attempts that I started to question this setup and wondered if this was the best setup for our situation.. this inquiry has lead to this posting.

In a perfect world, I would have an email server that:

• is easy to administer,
• supports automated mailbox setup/removal (currently I can just insert rows into my tables and the mailbox setup is done)
• supports current technologies, like grey-listing, DomainKeys, etc
• is secure
• makes the best use of system resources -- I want to get the 'best bang for the buck'

So what do you think? If I stick with this setup will life be grand? I am open to something new AND even taking the time to learn a new setup. If I do need to switch to something different, my only concern would be the ability to migrate existing mailboxes and messages over to the new setup.

Are there any other technologies or configurations that I need to implement to support the best deliverabilty rates?"

Comments

Full out of box solution.

[Anonymous Coward]

It's not free, but great support and full everything right out of the box, including IMAP, POP, SMTP, HTTP, authentication, account management, quotas and everything else you could possibly want.

If your company can't afford it, that sucks, but I'd rather use that than try and get courier, postfix, pop3d and squirrellmail or whatever to all work together.

http://www.sun.com/software/products/messaging_srv r/home_messaging.xml

http://www.clamav.net/

[kapplepc]

I recommend setting up ClamAv with FreshClam to filter out virus/worm type email. I have found it performs very well on my server. I have also found they have a very fast responce to new viri as they appear.

http://www.clamav.net/

Hard work.

[Seumas]

I support email servers for a living. I have for almost seven years - exclusively on Solaris, AIX and NT (though I do so on linux for my personal use).

While I think that your deployment is a reasonably sane one - as far as going the OSS/free route is concerned - I agree with the other poster here who said that having nobody to blame will be an issue in the future. When your job is on the line, it's good to have someone else who is supposed to know and fix everything for you when you are hard-up for solutions. Email administrators for the largest and biggest corporations in the world don't do it all in-house. Even they contract out for support for their enterprise level products. Because their customers and bosses expect great reliability and performance and features and they don't want to wait for several days (or longer) while you read some half-assed documentation on a website, chat up some gurus in IRC and post to some web forums and usenet groups hoping for help.

Also, there is nobody certifying that the products you are using will absolutely work together. And on whatever platform you're using. They may say they've tried it on it - but I doubt in many cases they will say it's been certified through a thorough internal QA process that weeds out a lot of bugs and such.

Also, when you really must have something fixed, you will either have to write the code yourself (laborious to do, without even talking about testing and implementing). If you have a commercial product and a contract, you can present a business case to get your issue some priority and have a fix. And you can always threaten to drop the product if they don't do what you want (it works more often than you'd think).

Even when full-fledged, thorough, all-encompassing high-capacity commercial servers - the position of email admin is a full time job for at least one or more people. Using a dozen different open source products and maintaining everything and keeping a constant sandbox environment to work in (you don't want to introduce upgrades or patches or changes on production, of course!) will consume all of your available time. If you are the full-time email admin here and that is your only responsibility - have at it. But if you have other responsibilities... I think the commercial path might be better for you.

Again - I'm an OSS advocate. Yet, I feel strongly that there are some cases in which commercial software and support is valuable. Depending on the specifics of your duties and position, this may or may not apply to you. But consider it. Especially if you're going to be fairly huge some day.

Another solution would be to contract with a third party. There are companies that do nothing but provide you with email solutions. They can do this based on very strong commercial products. These companies themselves will host and run the hardware for you. They will do all of the configuration and deployment and maintenance and administration for you. I'm not familiar with their prices, though - but do look into it. The upgrades and crashes and migrations are their responsibility. Meeting QOS is their responsibility. They will deal with the commercial mailserver vendor(s) for you. They already have support contracts with them. All you do is tell them how big of a deployment you want and you're set.

After working with commercial mailservers for several years, I was ready to setup a deployment of my own for my own personal project. Not having any funds, I decided I was going to go the OSS rout. Just figuring out what would work together and what wouldn't (you have to make sure your POP, IMAP and webmail servers all use the same mailbox formats. You have a gazillion options for accounting from LDAP to MySQL, countless authentication mechanisms, etc). It drove me nuts. It was at that point that I started to see the light and the real value in what I did with commercial products. Having an entire server that supports everything you could possibly need or want in an email solution through one install and one configur

Personally...

[Shads]

... after hosting using Exim3 and Exim4, Postfix, and Sendmail... if i were doing a "Large" config again (read 1000+ domains, 30k+ accounts) I wouldn't consider anything *but* sendmail. It's not the easiest, newest, or anything like that, but it does scale extremely well. The setup I'm currently using (about 10 domains, 70ish accounts) is:

Exim4 SMTP
Dovecott IMAP and POP3
Bogofilter
Spamassassin (SA-Exim)
Clam-AV

It's a rocking system, I'm currently having about 18000 messages a day tossed at me of which about ~17000 are spam. My personal accounts were getting about 2500 spam/day until I enabled all the anti-spam software and virus removal. I now get about 1-2 Spam a day and I've not had a single false positive.

For a small mid range setup I would probally use exim4. It's simple, has great features, and it's nice to have spamassassin at smtp time instead of having to process the entire message.

I don't recommend standard RBL's, however, the URI RBL's are *extremely* effective and an order of magnatude more sane in what they block (eg: if the message contains a link to viagraforyou.com it blocks the message, rather than blocking random dsl servers and /16 netblocks of ip addresses to catch a single spammer... some of the standard rbl's are nutzo.)

Theres a nice tutorial and informational link about using all the good features of sendmail and several additional ideas and theories on what is effective and what isn't at http://acme.com/mail_filtering/ the guy gets *insane* quantities of mail (mostly spam) and tells how he deals with it.

Synopsis: Large site- Sendmail, Medium/Small Site- Exim4.

Alot of people like qmail and postfix over sendmail and exim, but I just don't care for them having used them. Although if forced to choose between postfix and qmail it would be qmail.

Another place to ask advice

[hadaso]

You might want to ask your question also at the forums at emaildiscussions.com. There is a subforum there for "setting up an email service" and there are several active participants that are email admins running operations like yours or bigger (or smaller) that can give you good advice.