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The Exim SMTP Mail Server
A bit of history, first. Exim is currently in its fourth version, and is developed by Philip Hazel at the University of Cambridge Computing Service. The third release was accompanied by an O'Reilly book, also written by Philip, but there were enough fundamental differences that this release warranted its own volume. And what a book: more than 600 pages straight from the horse's mouth (as it were); you can't go wrong.
The structure is flat, being twenty-two chapters and two appendices long, but I'd say there were three main acts if you take it cover to cover. Philip begins with five chapters that introduce the reader to Internet mail, Exim, and some rudimentary runtime configurations. There's nothing to fear here, as the text is beautifully self-contained, covering topics from the DNS to routing lookups. As Exim's runtime configuration is both flexible and easy to read, the quite technical examples given early on can be understood without flicking to and from other chapters in the book.
The next four chapters cover in a rather succinct manner the parts of Exim that route and transport your messages. By this point you should have a grasp of the philosophy and design of Exim, which allows Philip just to give you the details. This section does feel most like a reference manual but I'm not sure there's another way he could present the information without confusing the reader. The remainder of the book covers each of the Big Features of Exim, one per chapter. I'm guessing that Philip just kept on writing until he ran out of features, rather than time or space! These chapters feel far more like the heart of the book, and the author treads a fine line between thorough process description and distracting technicalities. The two appendices cover regular expression syntax and special variables (both being available to Exim's configuration).
The book would be ideal if, for example, you manage a mail system on your own and don't have a great deal more admin experience close at hand. Its great strength is the vast number of scenarios that Philip has thought up; it seems that if you can think of something that you want the application to do, it'll be in there somewhere. At my site however we do have a good number of people who are familiar with Exim, so armed with a copy of the (equally well written) reference manual we can usually get along just fine.
Those expecting the chatty, irreverent style of an O'Reilly text may be in for a disappointment. Philip writes in a clear, precise manner, and obviously knows the subject matter (literally) inside-out; but there's no messing around and you have to be committed to learning about the subject in question. Having said that, I don't want these last two paragraphs to put you off. If there's even a whiff of a chance of you having to come into contact with Exim or its runtime configuration, then I can do nothing else but strongly recommend this book. The detail's there in spades, it reads very well, and is a fine complement to the reference manual.
For more information, see also the Exim home page, as well as this book's website. You can't yet purchase the book from American retailers, though if you're in a hurry, bn.com stocks the previous version. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.
If it's not broken, don't fix it.. But if you don't know it, don't learn it if there's something that's pretty much as good but much easier..
If I had to manage and administrate 5000 users, I'd vastly prefer Exchange to sendmail.conf.
You have to realize that your couple-thousand dollars saved is peanuts to your employers. The xerox machine is probably worth three times your 'savings'.
FUD! It seems that people don't realize that sendmail 8.12 now has an excellent security model and very advanced queuing features. In fact, in comparison qmail in particular looks very outdated.
I'm having trouble understanding why people here are trashing exim; as someone else already said, Debian uses it as their default mail server; it asks a few easy to understand questions, and just works. It's much friendlier than sendmail.
:-).
As for security, I haven't audited the code myself (honestly, have you?). However, I *do* subscribe to the BUGTRAQ mailing list, and have seen maybe two advisories on exim over the last two years -- as opposed to literally dozens for sendmail.
Oh, and the configuration file doesn't look like line noise
ERROR 144 - REBOOT ?
That's nice and all, but it's just half of what Exchange does. What about the calendars? Would something like PHPGroupware or one of the additional groupware scripts work with Outlook with Postfix for email?
Plus, if Outlook didn't work. They would have to reeducate the employees for the new system. You have to look at the big picture, to see the costs system wide.
m.kelley
life is like a freeway, if you don't look you could miss it.
Exchange does more than just email. What were you going to replace groupware things like calendaring with?
For those saying that exim code is a crap, Philip is
also the author of PCRE - Perl Compatible Regular Expressions, used in many others GPL softwares, like
postfix and apache.
So i will asassume, after looking the organized and helpfull exim code, that Philip codes very well.
Yeah, in light of the now cheap and ubiquitous Internet access, doing crazy stuff like UUCP and/or FidoNet feeds are just not very useful anymore.
... it was the ONLY thing, but now that there are so many systems out there that are better, why should anyone really continue to use it?
Besides, sendmail has had far too many security vulnerabilities and has grown far too bloated to be very useful, IMHO. Exim and Postfix are each remarkable mail systems in their own right and have way simplified the process of setting up a mail server. sendmail was once great
My journal has hot
There's nothing wrong with Postfix. My experience with it was that it seemed to be well written, solid, and capable. But I never could figure out the configuration files. I looked at the docs and read everything. But I never *grokked* them. On the other hand, Exim was a snap. I understood what I was looking at right away.
There are those who say exactly the opposite: they understand Postfix, but have no clue about Exim's configuration files. So now what I recommend to people is to stay away from Sendmail, then look at both Postfix and Exim. Pick the one that seems most natural to you, and stick with it.
If tits were wings it'd be flying around.
We call them religeous wars, but they are healthy disagreements about different approaches to problems.
Most people that speak strongly about VI and emacs have used both. Most people that speak strongly about Exchange versus anything come from a MS background where there is only one main way to do it. If the software is free, there is nothing preventing you from trying it out. If the software costs a couple of grand, you are commited.
Open Source Identity Management: FreeIPA.org
Answer me this then - how do I get all mail going through my qmail system (not setup by me, but I'm one of the admins) to go through SpamAssassin, but with per-user settings - i.e. after the decision has been made on who to deliver the mail to - without losing the ability to use .qmail files? Oh, and ideally without lots and lots more patching - there's a lot to be said for a stable system, but it's a real problem when the author doesn't seem to be planning any more releases, but the license forbids people from distributing patched releases...
Or to put it another way: qmail may be better for security, but I've had a lot of trouble working out how to hell to administer it, since it seems to ignore most of the tradition UNIX rules on 'how stuff works' in favour of newer, cooler, but random-seeming rules...
Paranoia isn't an infectious condition, it's a way of life
Yes. I've used qmail, Exim, Postfix and all of them perfomed better and delivered mail faster than sendmail. They're also easier to configure. I'm using Postfix now because I can't cope with /var/qmail and well Exim was pretty damn good too, but I got too used to Postfix. Haven't tried 4.x yet, but I was very pleased with Exim 3.x when I used it. I've also heard that zmailer performs well too. With the recent root compromise bug, Sendmail is not an option. Blah blah, it has new features and everything but it's still the same old crappy sh^H^H sendmail.
IMHO. Exim and Postfix are each remarkable mail systems in their own right and have way simplified the process of setting up a mail server.
;) It is wonderful... especially since the config files make sense (at least, it does to me). I never truly had control of sendmail because I didn't really understand everything in the config file.
I myself have switched to using Postfix both at work and for my home server
I've been using sendmail for aeons. Tried qmail, exim, postfix... even ran an exchange shop for half a decade and just migrated that to lotus last month, but for my smtp gateway relay box, I've been running postfix in test mode for three months now, in parallel with a sendmail box, and I'm really liking postfix a lot. It easily handles my multiple domains and convuluted interior-vs-exterior routing and filtering, with amavis, spamassassin and tmda. I like it a lot.
I run exim on over 400+ servers.
I use exim for the following reasons:
Maildir support
Mysql/postgresql/LDAP support for most any query (very flexible)
built in authentication (no wrestling with sasl)
built in nice filter language, but also still easy to tie in procmail.
High preformance compared to sendmail, close to postfix/qmail with split_spool_directory enabled.
The ability to tie on exim_sa or exiscan, and run spamassassin at SMTP time (reject before delivery).
Better security track record than sendmail.
Configuration without M4, or a headache.
Ralsky, is that you?
Come to think of it, I don't much care which spammer you are. You're a bottom-feeding thief, without even the courage to post as anything other than an AC, and your crap will never be welcome at any servers I'm in charge of. The sooner you're exposed for what you are, and thrown off the Internet permanently, the better.
Please accept my most cordial invitation to take your parasitical, thieving, spam operation and implode at your earliest convenience.
Bruce Lane, KC7GR,
Blue Feather Technologies
Admittedly, it's kind of a small one- but I wasn't able to find a single document for it online. Evidently you're supposed to look through the sample configs to learn things and read the comments.
For some reason I prefer exim's really incredible online docs to this approach- probably just because I can use the index.
Anyways, I'm not a zealot in this case, but I am an exim guy. While people complain that it 'may be' insecure, it doesn't seem to be that insecure to me where I've used it.
--Loki77
I understand Hotmail, I like Hotmail, and Hotmail works.
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