The Exim SMTP Mail Server 233
The Exim SMTP Mail Server: Official Guide for Release 4 | |
author | Philip Hazel |
pages | 621 |
publisher | UIT Cambridge |
rating | Recommended |
reviewer | Oliver Gorwits |
ISBN | 0954452909 |
summary | A thorough guide to the configuration and deployment of Exim v4.x |
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.
hefty? (Score:2, Informative)
Re:hefty? (Score:4, Funny)
Re:hefty? (Score:5, Funny)
You mean ... (Score:3, Funny)
Re:hefty? (Score:3, Informative)
Re:hefty? (Score:4, Insightful)
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
I agree. (Score:3, Insightful)
I myself have switched to using Postfix both at work and for my home server
Re:I agree. (Score:3, Insightful)
My Problem W/ Postfix (Score:2, Insightful)
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.
Millions (Score:3, Funny)
Yo Ralsky ! Loong time no see buddy !
All jokes aside, half a million messages/day isn't really that much. Does anyone know which software the spammers use ?
Exchange (Score:5, Interesting)
Sorry, I have to post this as an AC..
My employer has ~5000 employees across Canada. We have 8 or 10 MS-Exchange racks around the country (one per location and a big one in Ontario).
Two dual Xeons for primary and backup and another for the domain controller. I *know* how much traffic we have and this is gross overkill. Mind you, Exchange needs a lot of horsepower for the bloat. Anyhow, some rough numbers showed that we could eliminate all the Exchange servers with a *single* dual CPU FreeBSD 5.x box running Postfix.
Would the bureaucrats listen? No, in fact one fellow gave an ultimatum that if we didn't run Exchange, he'd quit.
So around the country we have little Unix systems popping up that act more reliably and without the spam (we use blackhole lists)
Re:Exchange (Score:4, Insightful)
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.
Re:Exchange (Score:2, Informative)
well, I haven't tried it, have no need for it.
There are dozens of Outlook work-alikes... (Score:2)
Re:Exchange (Score:2)
What about them? I'm honestly curious -- not trying to be an ass -- what tangible benefit is provided by having your calendar and email in the same application?
Re:Exchange (Score:2)
I'd call the fact the there are appllcations that do half the job as proff that you are wrong: someone started to create an equivelent desktop (spreadsheet, word processing, presentation manager, group scheduing and appointments, etc, etc, etc) instead of complaining. They just are not done yet, but they are still working.
And don't try to claim we over estimated the work involved, because those who estimated had no clue, while those who do the work rarely bother with estimates knowing that anything more
Re:Exchange (Score:2, Insightful)
Re: Exchange calendar replacement (Score:2, Informative)
Server runs on Linux and Windows, clients are running on Linux and Windows. Multiple node ability, i.e. servers across continents are possible.
Let him quit, then... (Score:2)
Re:Exchange (Score:2)
You might want to reread the parent post. He said he was using Postfix, not Sendmail! Postfix has a much better config file.
Exim on a Home Network (Score:5, Interesting)
I use Exim, because when I installed it with Debian, it asked about 5 reasonable questions, and then it just ran. That's it. There's no point in trying to learn Sendmail's complex file format, when we only need to serve 4 users. It's a great way to get an e-mail server up and running quickly for a small network. I was quite surprised, though, about the post above that said they use it for 1/2 million messages a day! I didn't know it could handle such a big load!
dochood
Asking /. (was Re:Exim on a Home Network) (Score:2)
However, I would like the workstation to deliver as much e-mail as it could on it's own, and only resort to the server if it can't.
The workstation is not allways on, it makes quite a lot of noise, so I shut it down if I don't need it.
Consequently, the workstation should relay the message on to the server if it can't deliver it immediately (for some sensible value of immediately), and have the server c
Re:Doesn't make any sense... (Score:3, Informative)
Re:Doesn't make any sense... (Score:2)
I use a Procmail Sanitizer [rubyriver.com] script to detect dangerous attachments, and it quarantines them, or it can strip them off all together. So, if someone sends my kids a potential virus, I get to inspect it myself, rather than trust my 9 and 11 year olds to deal with it!
I have a domain hosted on our company's computer, but rather than bugging the sysadmin (also the President of the company!) for this and that setup, I bring it down to my own computer with Fetchmail, and I can setup my ser
Re:Doesn't make any sense... (Score:2)
The PC generation are growing up. Five or six years ago, I would've trusted the 9 and 11
year-olds of the world, NOT to install a virus, more than their parents.
Props to exim! (Score:5, Interesting)
We used to use sendmail at work. The justification being that's what we always used, and that's what the support contracts listed.
Then the mail admin was on vacation for a week, and nobody noticed the security alert for the remote relay exploit. A spammer found us, and we had to shut down all mail for 6 hours until we could figure out what happened. And are still trying to get our IP off some spam lists.
Since then, we've gone to exim, and it justs works.
If anybody needs half a dozen sendmail books, let me know :)
Re:Props to exim! (Score:3, Informative)
Mandrake 9.1 defaults to postfix. I didn't look to see if sendmail was even an option.
Re:Props to exim! (Score:2)
Swansea University Computer Society [sucs.org] is happy to accept book donations... (and other donations, if anyone wants to buy us some new kit :)
Re:Props to exim! (Score:2)
Linux NET4.0 for Linux 2.4
Based upon Swansea University Computer Society NET3.039
Sounds like a worthy cause to me.
Re:Props to exim! (Score:2)
Re:Props to exim! (Score:5, Informative)
Red Hat includes both Sendmail and Postfix on their CDs - sendmail is just the default.
You can install Postfix, and then use "redhat-switch-mail" to activate Postfix. And with that, you're running a not-Sendmail mailer.
Re:Props to exim! (Score:2)
Re:Props to exim! (Score:4, Interesting)
Re:Props to exim! (Score:3, Funny)
Re:Props to exim! (Score:5, Interesting)
Assuming you didn't mean that sarcastically, in a "why would anyone need more than 640k of RAM" manner...
Because some of us don't like having our personal email stored on (or ever even passing unencrypted through) our ISP's systems.
A decade ago, well over half of my friends worked (mostly in some network admin style position) for local ISPs. Let's just say that I found this... "enlightening". Do not trust the privacy of ANYTHING stored on or passing over the net unencrypted. I don't say this out of paranoia, but real, concrete experience.
One friend (an extreme example, but probably more common than we'd like to believe) had a "stalkee of the week". He'd pick a random user, and read all their mail, check out what web sites they visited and what they downloaded, scan through their telnet, IRC, and any other unencrypted sessions... By the end of the week, he'd know more about them than their wives did.
Legal? Probably not (without a lot of evidence, he could have just claimed that he only monitored a suspected intruder). But could anyone catch him? Very unlikely, even if they knew about his "hobby".
My point with this little anecdote... Basically, you most certainly do have a good reason to run your own mail server, assuming you have even a passing interest in privacy.
Re:Props to exim! (Score:2)
I don't know why people drive in the left lane with their signal on going 10 miles an hour under the speed limit.
I don't know why people still are plagued by email viruses.
I don't know why a home user needs a 2.4Ghz CPU to check their email.
I don't know why you need to know why a home user needs an email server.
Re:Props to exim! (Score:2)
Because my ISP doesn't support IMAP or do any spam filtering and I'd like to access all of my substantial read email remotely from anywhere?
I am open to suggestions....
Why everyone uses Sendmail... (Score:2)
Because for better or worse, it's "the standard." It's the one most professional sysadmins are familiar with, and it's the one most other internet apps are integrated with.
I've been using Postfix, and it's a lot less complex. Theoretically that makes it easier and better. But every new admin/programmer has to learn it, while they already know Sendmail.
Re:Props to exim! (Score:2)
Um..., that could happen to any mail server.
An exim exploit could come out and only the untrained admins are in.
I use sendmail in a pretty complex setup. ISP-type virtual domain setup, LDAP datastore, and I have about 2, yes 2 exploits for the last year or so for which I was vulnerable.
PS. Configuring sendmail takes some reading, but upgrading sendmail is is simple as running the build script, doing a Build install, and then restart. The hard part was
Exim is no-nonsense, no worry (Score:5, Insightful)
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
Re:Exim is no-nonsense, no worry (Score:2, Insightful)
Simple address rewriting great for home use (Score:2)
As for security, I haven't audited it, either. But at least they say they take pains to attempt to shed capabilities as much as possible being "fully root" as little as possible. Besides, my Exim only receives mail from my LAN - it's send-on
bofh (Score:5, Funny)
Realizing that it was all very complex, we emailed all our employees their final message. It was a link to the SMTP RFC and a short list of instructions on how to use Telnet. Then we shut down the mail server and ate lunch.
Management reported an immediate profit increase projection for that month. While I'm sure this was due to productivity improvements facilitated by my fine IT department, some skeptical colleagues of mine think it was the mass exodus of employee resignations that took place around the time the new "mail system" went into place. I'm sure it was due to the rat problem in the cafeteria but nobody will listen to me.
Actually we've seen it handle... (Score:2, Interesting)
I like it. No it's not as configurable as sendmail, but nice and easy to deal with.
Re:Actually we've seen it handle... (Score:3, Interesting)
Of course it does not have the rewriting magic that sendmail is so feared for, so it does not support (for example) uucp addressing out of the box, but you can configure exim by it's variable-expansion (and lookups in host/address/domain/...-lists) to do any imaginable mailrouting you would possibly want in that RFC821/822 world of today.
I find the configuration by defining acls, (access control-lists), mailrouters (which convert addresses to methods
Configurability (Score:2)
The beauty and horror of sendmail is that its configuration system is a fairly general rewriting system. This has some peculiar consequences. Things that should be hard coded ((2)822 address parsing for example) are done in the configuration and things that should be configurable (eg, time delay in throttling) is hardcoded (or at best compile time options).
I'm not sure
Mod parent down... (-1, absolutely ridiculous) (Score:3, Interesting)
I've built big mail systems in the past four years around qmail and postfix both.
1. You need a sustained ~9 megabits per second link to handle a 5K message at that delivery rate. On top of that, there are tarpits, connection limits per MX host, and all manner of obstacles thrown up by ISPs (both nati
Re:Mod parent down... (-1, absolutely ridiculous) (Score:2)
What a steaming pant-load! I work for what you might interpret as a "spammer", we send out millions of messages today. (...) You need a sustained ~9 megabits per second link to handle a 5K message at that delivery rate. On top of that, there are tarpits, connection limits per MX host, and all manner of obstacles thrown up by ISPs (both national and local).
The sad thing is, it seems you are an intelligent individual. Working. For. A. Spammer. And the technical details you describe make your
Re:Mod parent down... (-1, absolutely ridiculous) (Score:2)
My hope is one day your job will be made illegal and with serious prison time attached. Then I might be able to remove the RBLs and SpamAssassin filters.
Re:Mod parent down... (-1, absolutely ridiculous) (Score:3, Informative)
I'll even address your points one by one, and I'll use small words so you don't get confused.
1. It had a gigabit eth card on a 45 Mb DS3
2. Who said it used a single IDE drive? No one in their right mind would use IDE in a production environment.
3. Splitting the Queue works wonders, and yes the load was off the charts. I never said this machine is still running, or even how long it ran like that for. It ran like that for about an hour, we then blocked the sp
Re:Mod parent down... (-1, absolutely ridiculous) (Score:4, Insightful)
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.
Re:Mod parent down... (-1, absolutely ridiculous) (Score:3, Funny)
You misspelled "have the contents of an entire clip of AK-47 ammunition emptied into you at point blank range."
HTH, HAND.
Philip (Score:2, Insightful)
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.
Re:Philip (Score:2)
Re: (Score:2)
Re:a few problems i encountered.. (Score:2)
suffix = +*
suffix_optional
Re: (Score:2)
Re:a few problems i encountered.. (Score:2)
For the second problem, look at this page [faqs.org], section 7. Can't help you with the first, sadly...
-Brendan
Exim isn't bogus software? (Score:2)
I just assumed that Exim was a bogus server name made up by the malware writer.
mmmmm religious wars..... (Score:4, Interesting)
That being said, I have experience on three of the "big four" MTA's out there (sendmail, qmail, and exim) and currently use exim on my personal site (which also hosts a number of mailman lists for OpenSource project and friends of mine) and it handle's about 20k messages in/out on a linux box.
I also use qmail on my work servers (cluster of quad-procesor ultrasparcs) and although I can't say I would have chosen qmail if I'd been in charge of building the servers (I inherited them from "the architect") it handles millions of emails a day just fine.
I can't say i miss m4 (although I know real sendmail admins don't bother with wimpy scripting languages), sendmail also served it's purpose back in the day.
Could exim handle the load on the ultasparcs? possibly, I haven't checked. Could I put qmail on my personal box? sure, but if Exim works, why not.
To comment further on one thing, Philip has a good explination of monolithic vs modular on the exim website, which explains why he does things the way he does. At least read it before blindly attacking the system.
Re:mmmmm religious wars..... (Score:5, Insightful)
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.
Re:mmmmm religious wars..... (Score:2)
Silly question, perhaps? (Score:2)
Isn't it just moving data to and from the network device? And wouldn't the network bandwith be the limiting factor?
Re:Silly question, perhaps? (Score:4, Funny)
As every spammer knows, the more you send out, the more $$$s you make!
Re:Silly question, perhaps? (Score:2, Informative)
Well, it's more work than just copying data. That's the easy part. Incoming mail messages must be delivered to the correct box. Some local users have mail forwarded elsewhere, which means rewriting some headers (to prevent mail loops and to document the path the message traveled) and stuffing the message back into the queue for delivery again. Other users take their mail locally, which means either appending to a file (which involves locking) or running a program like procmail to filter their mail. Eithe
Nice but... (Score:3, Interesting)
If only they upgraded books in a similar fashion to programs - some kind of discount from the previous version would probably encourage more people to keep their library up to date. (Although in this instance the migration from 3 to 4 was pretty painless.)
Discount Exists (Score:3, Informative)
Re:Discount Exists (Score:2)
Damn
A good thing (Score:4, Interesting)
Also, when you're connecting it to a database backend to pull all the delivery info as I and many others do, it's going to be orders of magnitude slower on both platforms anyway.
Hopefully in the future exim can polish off some more of the rough edges, but in the mean time, it's still a damn nice tool.
anything is better than sendmail (Score:3, Insightful)
"shared" email box redirection? (Score:2)
We have a 'black box' that does that now and would love to get out of that into something under our control..
And no we cant split up the external mail boxes into 'real' individual accounts to get rid of the problem, yet.. thats another year out...
web.de (Score:3, Informative)
Received: from [216.136.173.219] (helo=web14612.mail.yahoo.com)
by mx07.web.de with smtp (WEB.DE(Exim) 4.75 #2)
They have a Server farm of Linux boxen.
www.web.de
Maybe they are not as big as gmx.de (qmail on Sun), but from guessing the size of web.de (at least several million accounts) I would say it is save to say that exim is scalable.
Re:Why would I want to use exim? (Score:2, Insightful)
Re:Why would I want to use exim? (Score:3, Informative)
If you want a drop in sendmail replacement, then maybe postfix [postfix.org] would be a better choice.
Take the time to learn either qmail, exim, or postfix, you'll save more time in the long run.
Re:Why would I want to use exim? (Score:2, Interesting)
I've just spent enough time to learn how sendmail works that I don't see learning yet another MTA as being especially necessary. Besides, you can do some neat stuff with sendmail.
Re:Why would I want to use exim? (Score:2)
Re:Why would I want to use exim? (Score:5, Funny)
Security is the answer my friend.
Re:Why would I want to use exim? (Score:5, Interesting)
Re:Why would I want to use exim? (Score:2)
Re:Why would I want to use exim? (Score:2)
Re:Why would I want to use exim? (Score:2)
Unfortunately they don't appear to have upgraded in close on 4 years (they certainly have some machines running 2.12).
The Freeserve (or rather Energis Squared - the hosting ISP) mail system was the first in the UK, and probably in Europe, supporting over one million individual mail users. All the mail transport was done with exim on Linux, the mailboxes were on NetApp filers (Maildir structure). It was also one of the first mail systems with substantial anti-spam feat
Re:Why would I want to use exim? (Score:3, Insightful)
Re:Exim's design is bad for security (Score:3, Insightful)
Re:Exim's design is bad for security (Score:2)
True. Sendmail is very mature, and I find it integrates nicely with LDAP, SpamAssassin, MailScanner, etc. etc. etc.. I've never had a security problem in the eight years or so I've had it running here. I do load patches immediately, of course... but there have been more *nix kernel vulnerabilities than sendmail vulnerabilities during that time.
Re:Exim's design is bad for security (Score:4, Funny)
So, it looks like we'll have our MS-Exchange replacement afterall?
Re:Exim's design is bad for security (Score:3, Insightful)
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 release
Re:Exim's design is bad for security (Score:3, Interesting)
Yeah, well, that's why some qmail people are moving to Courier [courier-mta.org] instead.
I started with qmail, because I liked Maildirs much better than mbox format. But then I needed an IMAP server. And then I needed a webmail server. And then I needed e-mail filtering.
So instead of installing all the pieces separately, I just installed Courier.
While the DJB-style configuration directories are kinda interesting, I perfer Courier's more mainstream configuration files.
Still using DJBDNS [cr.yp.to] though. Small and sim
Re:Exim's design is bad for security (Score:2)
Virus scanners need to seek around in the mail files (or they buffer the whole mail in memory, which is even worse performance-wise). All modern virus scanners are running as daemons and are given a file name over a unix domain socket. To be able to give a file name of a file that contains the mail (and not some other postfix queue junk as well) to the virus scanner, you need to write a temp file
Re:Exim's design is bad for security (Score:2)
Heck, MS Exchange can do that!
ROTFL
Re:Exim's design is bad for security (Score:2)
So tell me, what do I need in which of the various config files - I'm talking s
Re:Exim's design is bad for security (Score:4, Informative)
Hold on just a second:
Yes, the daemon needs to be root initially, but it drops root privilages ASAP and does not, in fact run as root (unless you're insane and configure it to do so). Yes, it is a monolithic design, which may turn you off, but a remote exim exploit is not an automatic remote root exploit.
Personally, I like Exim a lot, and I haven't even upgraded to version 4 yet. Just be glad you have a choice of MTAs and aren't stuck with sendmail, as was the case not too long ago. (Though to be fair, sendmail is getting significantly better!)
noah
Re:Exim's design is bad for security (Score:2)
Yes, the daemon needs to be root initially
Actually, that's not true. I run all my Exim mail servers as a non-root user on a high port (like 51025) and use FreeBSD's IPFilter (ipnat, actually) to forward port 25 to this high port. It works like a champ.
To boot, none of my mail accounts are real unix accounts. They exist only in a PostgreSQL database (also running as non-root). To provide client access, we use Courier IMAP, also running as (you guessed it) a non-root user.
Nothing is setuid, nothing
Re:Exim's design is bad for security (Score:2)
The code is very well-written and and properly commented. Something you can't say about qmail. It's extremely suprising that DJB's software has so few bugs, given that it's basically unmaintainable.
Monolithic MTAs have one advantage which is extremely important for most users: much, much better debugging facilities to test configurations.
Re:Exim's design is bad for security (Score:2)
The qmail code is obvious enough not to need much commentary. You can judge the quality of a code base pretty well be looking at a) how many patches are available (if the code base sucks, nobody will want to patch it; people will rather write their own MTA), b) how big the patches are (if the code base sucks, you need to touch more in your patches to get your problem fixed), and c) how often it needs updates.
It
Re:Exim's design is bad for security (Score:2)
While it is true that indiscriminant comments do not necessarily improve a codebase, the qmail source has **ZERO** useful comments [1]. Literally zero. Worse, variables are randomly named. My first impression on looking at it was "Why was an open source release run through a shrouded-source processor?"
A maintenance programmer confronted with this codebase is screwed .
Re:Exim's design is bad for security (Score:2)
The problem with qmail is that the author is a screaming loony (albeit a very smart one).
We all know how support works for open source products: you use the mailing lists, IRC channels, mail to the author, etc. Woe be unto you if you ask a qmail question that was answered 3 years ago (and is thus archived somewhere), or worse yet, you ask for functionality that qmail doesn't have and DJB deems "inessential".
I've not even asked questions, but I've read the a
Re:Sendmail (Score:2)
Re:Postfix (Score:3, Insightful)
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, t
Re:Exim Vs Postfix? (Score:3, Informative)
Exim, on the other hand, is a small, simple, easy-to-configure, and very flexible little MTA. It's monolithic, so it doesn't have privilege separation, but it makes it very easy to do some things that are either impossible or very difficult with other MTAs. It may not scale as
Re:Super! (Score:2)
Qmail is light-years ahead of Sendmail, but if you think it's easy to use, you obviously have never even looked at Exim or Postfix!
And I'm sure someone could write a two or three pound book about Qmail if they felt so inspired. Heck, I could probably fill a qu