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Communications Operating Systems Software Unix

E-Mail Server Setup Advice? 67

Posted by Cliff from the not-as-easy-as-it-used-to-be dept.
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?"
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E-Mail Server Setup Advice? More

E-Mail Server Setup Advice?

Comments Filter:

  • Full out of box solution. (Score:3, Informative)

    by Anonymous Coward on Friday August 26, 2005 @08:00PM (#13412404)
    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 [sun.com]
    • Don't use the Sun Messaging if you want to keep your clients happy. My university used to run QMail with Horde/IMP and it was kick ass (I subsequently moved my mail servers to that combo). They then for some unexplained reason (probably easier to admin or they got a deal since they are a university) they switched to this piece of shit software.

      IT FUCKING SUCKS. You have about 1/10th the features and it runs significantly slower (I cannot verify the hardware is the same but the previous systems were IRIX on

      • I don't know who modded you as a Troll, but they should have their mod rights revoked, or get paid by Sun.

        I have also been on the user side of Sun's Messaging service. I can't express how frustrated I am with it. Calendaring is a joke. The web interface is behind what most OSS products were years ago. Whatever you do, don't rely on the "JES Connector" to get your Outlook client to interface with the calendar. Have my entries are missing through outlook, but show up fine in the thin client. Speaking o

    • ... Microsoft Exchange Server 2003 Enterprise Platinum "This One Is Really Secure" Edition. Nothing like good old Microsoft products.

  • http://www.clamav.net/ (Score:3, Informative)

    by kapplepc ( 100101 ) on Friday August 26, 2005 @08:07PM (#13412436)
    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/ [clamav.net]

  • Why Postfix/courier? (Score:3, Informative)

    by Lenolium ( 110977 ) <rawb.kill-9@net> on Friday August 26, 2005 @08:26PM (#13412529) Homepage
    So, I have a mail system setup, it's running around 70 domains, and 500 email accounts.

    I am using courier as the mta, and courier as the pop, and courier as the imap.

    The courier makes a fine MTA, but you do have to tweak a few of it's settings to make it more wideopen to allow it to connect to misconfigured exchange servers.

    Other than that it has been great. I have a email account management system that I wrote that lets each domain have admin users that can add and delete accounts as they please.

    I have SpamAssassin setup for some users (most of them post their email addresses in plain text on their websites) and even with that load, there is still plenty more capability in this little server.

    Now, if you want a system that scales to tens of thousands of users, you are going to need to get something a little bigger than this, you are going to need to get a mail system that can distribute the messages over a number of servers. That is something I have not researched.
    • Now, if you want a system that scales to tens of thousands of users, you are going to need to get something a little bigger than this, you are going to need to get a mail system that can distribute the messages over a number of servers. That is something I have not researched.

      It might be called Hula: http://www.hula-project.org/ [hula-project.org]

      • Cyrus IMAP does this using the MURDER protocol, which has been submitted as an Internet RFC. Cyrus also supports the SIEVE protocol (another Internet RFC) for server-side filtering.

        This is the solution we will be migrating to this year (Postfix, Cyrus, SquirrelMail) for ~1600 accounts in 1 domain, with another setup for next year using ~15,000 accounts across 15 domains. User accounts are stored in an OpenLDAP directory.
    • How do you handle vacation messages? I'd like something users can turn on and off but there seems to be no built in function in courier
      • It's implemented by using a .mailfilter file in the user's home directory per the descriptions in the maildrop [courier-mta.org] docs. How to change the .mailfilter file is left as an exercise to the reader but Courier's own webmail has support for it.
        • Yes, thats the point I had gotten to. I had hoped someone had developed a "user easy" way of doing it. Guess I'll have to break down and write it myself :P

          • I had hoped someone had developed a "user easy" way of doing it.

            Oh, they have. Zillions of ways actually. There's no standard to make an e-mail client tell the server that the user is on vacation, so you end up with webmail-powered kludges, one or more for every webmail/MTA combination there is. You should be able to find one for whichever webmail program you're using - but you're almost guaranteed that another webmailer got the "good" vacation kludge and you got stuck with one of the bad ones.

    • Cyrus (Score:2)

      by phorm ( 591458 )
      I'm a courier user myself, but I was talking with one of my co-workers about IMAP servers and he said that Cyrus - though a bit more of a pain-in-the-ass to configure - was generally more efficient under scenarios with a high userbase.

      I can't recommend it from experience, but I would trust the advice of this particular individual.

      For smaller userbase, I'd have to say that courier was pretty painless to configure and reliable as well.

  • Courier IMAP (Score:3, Informative)

    by embo ( 133713 ) on Friday August 26, 2005 @08:35PM (#13412569)
    Courier IMAP is running to support both IMAP and POP access to the mailboxes.

    I would switch to dovecot [dovecot.org]. I found the performance to be quite a bit better than Courier, and it seemed more stable as well.
    • Courier IMAP is pretty poor. UW-IMAP is a piece of crap. Binc might be good now (it has the right goals), but was too immature when I looked at it.

      Switch to Dovecot. Also, if you haven't already, switch to Maildir for your storage format. The mbox format is a disaster when dealing with IMAP clients like Apple's Mail, which opens multiple folders at once, thereby locking them all and blocking mail delivery.
      • Also Maildir is much better for backup/recovery of messages. rsync or rsnapshot work beautifully with Maildir. Performance from LookOut! is better too.
    • I *LOVE* Dovecot!

      If only it did shared mailboxes, it'd be perfect.
    • I had the same experience with it... until i upgraded to the newest version. Config file stopped working, had to rewrite it. And after i did that it just wouldnt work like it used to, it just says "Internal login failure".

  • Hard work. (Score:5, Insightful)

    by Seumas ( 6865 ) * on Friday August 26, 2005 @08:46PM (#13412625)
    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
    • You know I was really with you until you got to the part about no IMAP OR Webmail... Now I'm rather dubious... Your users ALL have laptops or never go on vacation/offsite and still want their mail? Your company allows the security risk of downloading mail to untrusted machines?

      I'm really confused here. You sound like a smart guy but this last decision makes you sound like a duffer, or you have been using Out of the Box for way too long.
      • As I said, the OSS deployment is for a personal project. I run a huge website and it sends out thousands of emails per day (notices, registrations, password reminders, etc) and recieves several times that (75% of which is spam).

        Since there are only a handful of users, POP is just fine. Or in my case, just ssh-ing in and firing up mutt on the server.

        If I were offering an email service to people, I'd spend more time on one of the five zillion webmail "solutions" out there or with IMAP. Of course, that'd still
        • I found the following to be very easy to deploy and maintain, requiring only a minimal amount of time. Granted we only have about a hundred email addresses but, still I spend very very little time maintaining this setup: QMail (SMTP and POP3) QMailScanner with SpamAssassin and ClamAV BincIMAP And its all running off a 1.8GHz P4 (granted with high load).
          • What are you guys doing getting 1.8GHz machine into high load?

            I run a Celeron300A(OC to 450Mhz) with 192Mb of memory and regular IDE disk. We have about 150 e-mail accounts, all of them get filtered thru SpamAssassin and ClamAV, and the load is about 0.25!

            Debian Postfix-Amavis setup.

            Oh, that machine also handles some 10 orso low-traffic webpages, has UW-IMAP + squirrelmail + IMP.

            How in the hell can you get 1.8Ghz machine on his knees with 100 mail accounts?
            • Well, it had 128MB memory. And the reason it really gets loaded down is because hourly I have clamscan scan everybody's mailboxes including inside zips, rars, etc. (this takes a while, but its mainly to ensure that I don't dish out a virus thats discovered after the mail has been received). And also, its the proxy server for the local LAN (about 200 computers). Now that I updated the RAM to 512 its not bad though. And also, all connections use AUTH over TLS/SSL (including SMTP for outbound connections)
              • Ah, i see - re-active scanning might take a lot of time.

                Load is usually specified as of output /usr/bin/uptime binary or as output of /usr/bin/top.

                Cat /proc/loadavg on linux box shows load too.
    • Man, either the astroturfs are out in force, or no one here can read. This is the second message that says 'Everything might work together or might not, who knows? Commercial solutions tend to be easier.' (And explictly says 'I'm an OSS fan'. What, you guys got the same script?)

      Well, let's look at what software he's talking about.

      Postfix.
      SQLGrey: A policy server for postfix (In fact, it won't work with anything else. 'Policy servers' are a postfix invention, designed to provide half of the functions of a

      • I'm sorry, but I've dealt with far too many email admins who didn't have a clue and were responsible for an entire enterprise structure that could barely manage simple tasks, much less figure out a complex mish-mash of OSS solutions. It isn't that they're deficient, but you have to plan a deployment for the level of administration that is going to be afforded to it. Someone who is posting to Slashdot of all places - to get a review of their deployment plan - is (and no offense to the submitter) probably not
        • I dunno, maybe you're coming from six years ago.

          But it's not as complicated as it could be, if sane choices are made.

          That means absolutely no sendmail. That means Maildirs, so you don't need any file locking at all. That means users stored in one place, be it SQL or LDAP, and not a brittle text file under any circumstances.

          A lot of that is choices, and many people don't know how to make good ones, but this guy does. In fact, he's managed to chose exactly what I chose, three years ago, at least for the b

    • 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.

      Speaking as an email admin for an $80bn

    • Outsource It (Score:3, Informative)

      by Vagary ( 21383 )

      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 res

  • It is easy to use, can be expanded to cluster servers and is reliable.

    Works with squirellmail, and a bunch of other cool features. Plus the name of the company is kind of cool.
    http://www.stalker.com/content/solutions.htm [stalker.com]
  • If I were you, I would ask myself at least this:

    "If the building the server lives in falls into the center of the earth, but my boss wants the mail back up (not necessarily with their data, just live again), would I be able to put Postfix, SQLGrey, LDAP auth and Courier back together in less than 4 hours except for user accounts?"

    If you are sufficiently detailed enough to pull that off within 4 hours except for user accounts, you probably have the bits you need to wing all the rest of the bells and whistles

  • Suggestions (Score:3, Informative)

    by Bruha ( 412869 ) on Friday August 26, 2005 @10:47PM (#13413124) Homepage Journal
    Check out inter7.com

    They use Qmail which is open source. Who told you it was not?

    Qmail is highly scalable and I think www.qmailtoaster.com and a few other sites provide great setups that allow you to set quotas and such.

    large game sites use qmail.

    Hell hotmail.com uses qmail to send emails. Not sure about the rest of it.

    Inter7 can get you setup properly and provide maintenance if you have problems but otherwise their setups are self manageable.
    • Qmail is a fine MTA that is really beginning to show it's age, and was written by a control freak. If you want to run a Qmail system, you're basically forced to maintain your very own patch repository because the base package is almost completely inadequate these days. You cannot do spam filtering, virus scanning, SMTP authentication, TLS, or anything djb didn't believe was important.

      I switched from qmail to postfix, not because qmail was defective in any way, but rather because postfix is maintained. S

    • A variation on a theme: build a FreeBSD toaster based on Matt Simmerson's recipe at www.tnpi.biz. There's a very large user community that helps out via mailing lists, the instructions are outstanding and it's got all the goodies: Webmail, tarpitting, antivirus/antispam, web-based config or command-line config, etc. Matt and others offer for-fee troubleshooting and/or set-up, but chances are you won't need it. And it is secure as hell.

      Yeah, I run it -- consider me a satisfied customer/fanboy.

    • See the qmail license. You cannot modify and distribute qmail, and you cannot distribute binaries.
  • Download this [probsd.net].

    Then, assuming you know how to write PHP code, throw away the php. It's not that good. It can't handle fields being added to the database. But writing php for database manipulation is trivial, so I'll assume that's what you're already doing.

    Anyway, what you need from 'vmail' is the 'maintain' perl script. It's fairly easy to understand. Basically, you want a 'new' table in your database with new email addresses, a 'deleted' one for deleted addresses, and a 'moved' one for moved emails. So in

  • I'm surprised nobody has mentioned dbmail [slashdot.org] yet. It's a nice prepackaged substitute for maildir/courier/mysql virtual users, etc... It's not a substitute for everything you require, but it will simplify your most common admin tasks.
  • Make sure you turn on the requirement for HELO and turn off the SMTP VRFY command.

    If you do something that's going to drastically alter your server's behavior, do 'inet_interfaces=localhost' to test, then restore to 'all' when you're sure it's working.

  • Personally... (Score:5, Informative)

    by Shads ( 4567 ) * <shadusNO@SPAMshadus.org> on Saturday August 27, 2005 @12:42AM (#13413578) Homepage Journal
    ... 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/ [acme.com] 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.
    • I am a BOFH at a very large email hoster. We use Postfix. It scales up very well, and is rock solid.

      BTW, those graphs are pretty small compared to our numbers.
  • I would suggest setting up a number of outgoing relays. Group your customers into tiers of trustworthiness. Everyone goes on server 1 to begin with. Anyone who behaves for 3 months gets moved up to server 2. Anyone who behaves for 3 months there gets moved up to server 3. Anyone who misbehaves gets moved back down to server 1, and anyone who continues to misbehave on server 1 gets disconnected. This ensures that your non-spamming customers end up with more reliable delivery.
  • I really wouldn't worry about it. Hardly anyone uses it to block email since he states on his site that it has a lot of colatteral blocking.

  • QmailToaster (Score:2, Informative)

    by T4D ( 602592 )
    You might want to check out QmailToaster [qmailtoaster.com]. It's free, supports multiple domains, has a web interface, and has SPF and ClamAV integration.

  • Postfix + Cyrus + SQLGrey +DSPAM + Mysql (Score:3, Informative)

    by madstork2000 ( 143169 ) * on Saturday August 27, 2005 @12:27PM (#13415886) Homepage
    I own a small hosting company. I have setup my business so that all accounts (except shell accounts) are stored and authenticated against MYSQL databases.

    For that reason I chose Cyrus as the actual local mail system. It supports IMAP / POP3 can be scaled pretty easily. And despite reports that it is hard to configure, I have found that it really is not too bad if you keep things simple.

    Currently I host about 3000 domains, and roughly 5000 email accounts, though most are nothing more than SPAM traps.

    If you do go this route, the key is a reliable and robust MYSQL server(s).

    The main advantage of MYSQL based virtual acounts is web-based management is trivial. ADD / UPDATE / DELETE can be done simply by updating a record.

    The draw backs I have found are: a database/DB Server is an additional point of failure. Replication has been a bit tricky at times. Do not run DSPAM in the same database as your user / hosting accounts.

    -MS2k

  • Another place to ask advice (Score:3, Informative)

    by hadaso ( 798794 ) <account@3.14159s ... aso.net minus pi> on Sunday August 28, 2005 @02:49AM (#13419698)
    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.

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