Sendmail Performance Tuning 216
| Sendmail Performance Tuning | |
| author | Nick Christenson |
| pages | 256 |
| publisher | Addison Wesley |
| rating | 9 |
| reviewer | Andy Murren |
| ISBN | 0321115708 |
| summary | Compact but well-constructed book; shows you ways to cost-effectively improve your sendmail setup, and much of the rest of your system along the way. |
This book was very easy to read and kept moving along. While I did not find it as much of a page turner as Douglas Adams' Hitchhikers Guide, it did keep me interested. One word of warning though: do not read this when you are tired. You will miss some really good information and have to re-read parts.
I was surprised and very pleased with how much I learned about so many things about Unix, networking and hardware while learning more about sendmail. There is a wide range of information presented that readers at almost any skill level would be able to use. The writing style and use of language was easy to read. The wealth of information packed into the pages of this book I found immediately usable on my Linux boxes and for my job.
I think the only drawback to the book was that there was not more specific sendmail information. Due to the nature of the topic, a lot of the book is devoted to how Unix systems work, more than specific sendmail configuration tasks. Time and detail is spent on other more important considerations such as logging, disk performance, test planning and file systems.
Chapter 1 gets us started with an overview of tuning in general. One of the more important themes of the book is established up front: It is that a cost/benefits analysis should be done for each step.
Sections 1.5, "Tuning Isn't Always Necessary" and 1.6, "Not So Fast ..." establish baseline considerations for making a decision on what, if any, tuning efforts should be made. Throughout the book Christenson reminds the reader to decide on a path that is most cost effective for his organization. Is it the most cost-effective use of the company money and time to have the IT staff hand-craft solutions, or is it better to throw some hardware at the problem?
Let's face it -- if you are running sendmail for a small company and only move a few hundred emails a week, how much performance tuning do you need? If, however, you are running an ISP, a mailing list server or a medium- (or even a large-) sized company mail server, then you need to tune your mail server. This is the book for you. The information in this book, while oriented for sendmail, is actually applicable for tuning any Unix based Mail Transport Agent (MTA) server.
Each solution is an individual matter, that is wholly dependent on several factors. Some of these factors are: volume of email, what the main use of the email system is, how the end users interact with the system, what hardware is being used, how much bandwidth you have and much time and money you have to throw at the problem. Of course, what management considers important is the overriding factor in all decisions.
Chapter 2 is a ten-page introductory overview to sendmail, covering versions, obtaining the (Open Source) code and building sendmail. One of the important things covered is the queue and message spool layouts and permissions. This is helpful for making sense of things later in the book.
A few very important pages are spent on creating the .cf file and why you should use M4, the macro language, for managing the configuration files. Having hand-crafted a .cf file myself several years ago then having to deal with maintaining it, I can vouch for the wisdom of using M4.
The maintainers of sendmail update the M4 macros for new features and changes. The 200 - 300 lines of M4 macro files are converted into a 1500to 2000 line configuration file. While it may be easier to figure out the configuration file to make changes, those changes may not be valid from one version of sendmail to the next.
Christenson admits that he does not always use M4 when in a rush or to test some things. What he does is copy the working configuration file to sendmail.cf.REAL before making changes and updating the .mc file afterward.
The next chapter, Chapter 3 'Tuning Email Relaying' starts with an overview of the email relaying sequence. Most of the discussion in this chapter is not sendmail specific. The importance of data synchronization is emphasized here. Section 6.1 of RFC 2821 is quoted, where it states the email server 'MUST NOT lose the message'. Once that is stated and understood all of the requirements that are discussed in the rest of the chapter are clear.
The next 17 pages are spent discussing how file systems, networking and effective use of file space support, and can detract from, meeting the edict of the RFC. For me, these sections are some of the most interesting, filled with information presented in a concise, readable and detailed manner. I learned a lot about what impact some very basic decisions have on email performance. I also learned how much better I could have made the email servers I have worked on. I will be turning to this chapter the next time I am putting together a box, be it a web server, mail server, file server or even a workstation or laptop. This is a great chapter that can help with any system configuration.
Email reception is covered in chapter 4. Different strategies for verifying recipient, tuning POP and IMAP are covered. Effective use of Local Delivery Agents (LDAs), including procmail, is covered here also.
Additionally, an excellent discussion of storage systems, including disks and solid-state disks, is in this chapter. The sections covering RAID levels, benchmarking and use are well written and informative. Available options on drives, ATA vs. SCSI, Solid State, are just as well done. Section 4.4.2, 'Stupid Disk Drive Tricks,' has some nifty information about how to set up disk drives for even better performance.
Sending email is the next chapter. Here we see some more sendmail-specific information. Tuning of mailing lists and mass mailing is part of the discussion here. One of the more important sections is 'Draining Queues.' How backups are caused and what to do to recover are discussed in this section. This has good information that can be used with any MTA.
One of the most important chapters for me is Chapter 6 'Configuration, Security and Architecture.' Sendmail specific configuration and tuning options are discussed. Section 6.1 covers configuration and is in many ways the heart of the book. This is where sendmail directives that can directly impact performance are covered. How a system's architecture (and DNS) is laid out can have a significant impact on performance.
The section on security is good, but brief. Most of the discussion is on privacy and stopping spam. The use of Transport Layer Security (TLS) is covered in less than a page. With a smattering of security in other parts of the book, this is the sum total of the security discussion of the book. Considering some of the problems with sendmail in the past, I would have liked some more information on this topic.
The next two chapters, 'Finding and Removing Bottlenecks' and 'Load Generation and Testing,' are good, solid, well-written sections that are applicable to most any email system. We are given some effective ways of making systems run better, and how to prove that the system actually does work better. This is where we justify to the boss that the work we have done is really cost effective.
Chapter 9, 'Conclusion' is basically a very brief wrap up and a list of books Christenson thinks we should read.
My own conclusion is that I have learned and relearned a lot of things about Unix and email. Even if you do not use sendmail, I recommend this book without reservation. It is an excellent reference on general system performance tuning, with information on making your sendmail installation run better.
Table of contents
- Introduction
- 1.1 Performance Tuning Examples
- 1.2 sendmail Versions Covered
- 1.3 Definitions
- 1.4 Email Server Tasks
- 1.5 Tuning Isn't Always Necessary
- 1.6 Not So Fast...
- 1.7 Email System Profiling
- 1.8 General Tuning Ideas
- 1.9 Summary
- Sendmail Introduction
- 2.1 Obtaining Sendmail
- 2.2 Building Sendmail
- 2.3 Creating a .cf file
- 2.4 Why Use M4?
- 2.5 System Setup
- 2.6 Summary
- Tuning Email Relaying
- 3.1 What Happens During Relaying
- 3.2 Synchronization
- 3.3 File Systems
- 3.4 File Space
- 3.5 Networking
- 3.6 Summary
- Tuning Email Reception
- 4.1 What Happens During Email Reception
- 4.2 Recipient Verification
- 4.3 Storage Systems
- 4.4 Disks
- 4.5 Solid State Disks
- 4.6 POP Tuning Specifics
- 4.7 Message Storage Hashing
- 4.8 IMAP Tuning Specifics
- 4.9 Summary
- Tuning Email Sending
- 5.1 Mailing Lists
- 5.2 Command-Line Message Generation
- 5.3 Draining Queues
- 5.4 Another Mailing List Strategy
- 5.5 SMTP PIPELINING
- 5.6 More Notes on Mass Mailing
- 5.7 Summary
- Configuration, Security and Architecture
- 6.1 Configuration
- 6.2 Security and Performance
- 6.3 Other General Strategies
- 6.4 Summary
- Finding and Removing Bottlenecks
- 7.1 Kernel Parameters Run Amok
- 7.2 The Quick Fix
- 7.3 Tools
- 7.4 syslog
- 7.5 Removing Bottlenecks
- 7.6 Summary
- Load Generation and Testing
- 8.1 Test System Setup
- 8.2 Testing Tools
- 8.3 Load Testing Pitfalls
- 8.4 Summary
- Conclusion
You can purchase Sendmail Performance Tuning from bn.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.
Oh Yes! (Score:4, Funny)
apache and sendmail books not quite useful (Score:4, Insightful)
I have administered NIS+ apache, and sendmail, and these topics are so vast, that buying books doesn't help. However searching through google/deja does help a lot.
But that is just my opinion....
Sendmail tuning? (Score:4, Insightful)
Tuning Sedmail is about as smart as tuning MS Exchange. Both are fat, bloated, and have a history of secutiry holes. Performance tuning Sendmail is like performance tuning an AMC Gremlin made out of spare junkyard parts - you end up with a cobbeled peice of crap with a spoiler.
Sendmail is so bloated that it apparently takes books to get decent performance out of it.
Sendmail doesen't fit the one of the core Unix ideas - use simple, robut and elegent programs, chained together, to do cool things.
Check out Postfix or Qmail for decent replacements to Sendmail. Enjoy the performance of well toughtout software. Postfix was so easy to use, that I went from reading the man pages to a working system in one hour.
Re:Sendmail tuning? (Score:3, Insightful)
Robut? You sound like Dr. Zoidberg on Futurama.
But to stay on topic: We use sendmail at all of our locations because we enjoy the extremely powerful customizability. Yes, it is a little disconcerting trying to disect sendmail.cf, but once you get the hang of it it's not bad. I have never had to do any performance tweaks either.
Re:Sendmail tuning? (Score:3, Insightful)
There are a lot of good thing about Sendmail - but I'm afraid, for me, the good things are hidden in layers of suckyness.
If someone sat down with the source code and only used the delete key - you could strip out the crap and make Sendmail cool. And, of course, change the sendmail.cf format to resemble somthing human readable.
It's kind of like looking at a fat-girl, and saying to yourself "She'd be cute if she lost a few pounds". You know it's never going to happen, she'll just keep eating the Happy Meals. I fear Sendmail will keep on getting bigger as well...
Re: (Score:2)
Re:Sendmail tuning? (Score:4, Insightful)
I guess it works okay, but only a badly twisted mind could have devised the configuration system that qmail uses. Once you add one of the various virtual domain hacks it becomes nearly impenetrable. Then you try to integrate a mail list manager or spam tool, and before you know it, you're waist deep in GID's and SUID bits and log files, and you find yourself trying to read a Google translation from the original Slovenian.
Re:Sendmail tuning? (Score:2)
DJB is darn smart, but his software is not truly 'open', and as such, has a dubious future. His license, is just as much of a dead-end as propiatary software, so I chose to use Postfix and haven't regretted it at all.
Postfix is simple, sane and easy to chain to other cool programs. It's quite easy to get Postfix to hand off an peice email for processing and retrive it at almost any point in the delivery chain.
Re:Sendmail tuning? (Score:2)
Re:Sendmail tuning? (Score:2)
Re:Sendmail tuning? (Score:2)
Again, IIRC, Postfix has a local exploit. To my knowledge, it has never been fixed.
Re:Sendmail tuning? (Score:2)
Re:Sendmail tuning? (Score:3, Informative)
with -- has been closed. Please stop spreading
misinformation.
Re:Sendmail tuning? (Score:2)
First of all, the hole was NOT small.
Second of all, I did not assert that it was current information. Go back and read what I said.
Please stop wasting bandwidth.
Re:Sendmail tuning? (Score:2)
locally-submitted mail to be deleted. I say "theoretically"
because it was quite difficult. I am not aware of any
reports that this vulnerability was ever exploited in the
field.
Re:Sendmail tuning? (Score:3, Informative)
Found this by typing, "postfix local exploit" on google. Seems there were tons of other hits on this too (about 6,900).
Re:Sendmail tuning? (Score:2)
Go figure...
Re:Sendmail tuning? (Score:3, Informative)
Postfix has solid anti-spam measures, fantastic performance, readable config files (that are well commented from the start... heck there are about 10-20 comment lines per config line), and you only need to set like 3 lines in the config to get a working mail server.
Re:Sendmail tuning? (Score:3, Informative)
The thing that Sendmail did well, address rewriting, is irrelevant for today's net, and can be done more readably in many other ways. Even a Perl script is much more readable :-) Installing one as a Postfix transport is trivial.
I'm surprised that there isn't more business action around Postfix.
Bruce
Large Canadian ISP is using it (Score:3, Informative)
clients, dumped their Sendmail-on-Solaris servers in favor of Postfix-on-FreeBSD and have never been happier.
Re:Sendmail tuning? (Score:3, Interesting)
Whoo-hoo! Replying to a Bruce post. :-P And not agreeing(sp?) with him.
I have to say that the address rewriting in sendmail is necessary. And because of it, sendmail was the only option for what I needed to do a short while ago. Basically we were using fetchmail to retreive mail from a single multidrop box from our ISP for our department email. Then, for the relay outbound we had to determine if the email was to be sent locally or back up to the ISP if the user was not in our department. Then, after all that I still needed to add amavis(sp?). Sure, it was not the cleanest/most readable .cf file, but it was the only thing I could get to do the trick. When looking at postfix I did not see anything that allowed me to do the address rewriting to the granularity required. Then looking at qmail, well... to avoid four letter words I'll stop there.
The best part of sendmail is actually its obtuse feature set. Its similar to cars with 4wd, most poeple don't need it, but when you do need it, its mighty nice to have.
More MaxRunnersPerQueue speeds sendmail (Score:3, Informative)
Sendmail's default configuration is very conservative with respect to both your machine resources, and the resources of those with whom you exchange mail.
Run sendmail with
(or something bigger, if you want) and you can get past the biggest hurdle in sendmail performance -- by default, sendmail will handle all outgoing messages in a single queue. (Both qmail and postfix use multiple queues and/or runners by default.)Sendmail can relay messages without doing any disk I/O, thanks to the asynchronous I/O libraries; coupled with multiple queue runners, it's hard to get faster performance out of any MTA.
Re:Sendmail tuning? (Score:2)
The thing that Sendmail did well, address rewriting, is irrelevant for today's net, and can be done more readably in many other ways.
address rewriting is irrelevant... Okay....
Use address rewrite rules to pass messages with addresses that other process expect not ones that the user provides. Eg. user setups 'user@mail.domain.tld' and cyrus only knows 'user@domain.tld'.
Address rewrites are useful for rewriting addresses when clients pull a random domain from system configuration, and sends that out in a message.
rewrites are handy when to split users between servers, etc. There are lots more cases.
Even a Perl script is much more readable :-) Installing one as a Postfix transport is trivial.
Yeah, you do that. That's just 'screaming' performance, Bruce :)
Re:Sendmail tuning? (Score:2)
I couldn't disagree more. Address rewriting is essential on today's internet, and I've had to do a lot of it (both professionally, and to a lesser extent on my home systems). Without the flexibility sendmail provides, I'd be sunk. Sure, there are other alternatives, but since sendmail does everything I want without problems, why change? No, the cryptic config file isn't sufficient reason. Firstly, it's no more cryptic than other more "geek approved" tools, such as perl -- once you know what the different symbols mean, both start to make sense. Secondly, it's hard to provide the power of sendmail in a configuration language that's much less complex.
Re:Sendmail tuning? (Score:2)
Agreed. The book I'd like to see is "Migrating to qmail from sendmail." (or even "How to Convince Your Boss to Adopt QMail and Stop Throwing Hardware at Sendmail."
Re: (Score:3, Interesting)
The right tool for the right job. (Score:2)
Sendmail kicks ass.
In a former life, I had to build a mailing list manager that handled content generation, sub/unsub, bounce management, etc. for a large number of mailing lists that had to do about 1.3 million messages in 4 hours.
Without going through the whole set up, there were slave boxes that just delivered mail. They used pieces of postfix, which did a good job (I like postfix, BTW, my current company's primary mail server uses it).
The primary machine used sendmail. Once you get over the horror of writing a
A lot of people who don't really know what they're talking about rag on sendmail, echoing some very valid complaints that are mostly only of historical interest now. The most valid complaint these days is that it is arcane to configure. My take is, sure, it is, as it should be. Handling large volumes of email is second only to nntp for placing a heavy load on all sections of a network. If you don't know what you're doing, you shouldn't be doing it.
I use postfix because it is easy now, we're only handling a few thousand messages a day.Should that change, I'm back with my old pal sendmail.
Re:The right tool for the right job. (Score:2)
I mentioned this in an earlier post, but I'll say it again for good measure: I've never edited a .cf file in my entire life, but I've been able to pull some amazing functionality into an (easy-to-read) .mc file.
Other than that, I agree with you. I use very few non-standard features in Sendmail. However, every time I've had some seemingly-bizarre need arise, it's been extremely comforting to find that Sendmail already incorporated the capability, and that I didn't have to replace my current working MTA with something else.
Re:The right tool for the right job. (Score:2)
My normal pattern was to hack the
Don't get me started on when we had to hack the source to get something that would check a remote site for the existance of a given username... _that_ was bad.
In any case, yes, sendmail has a long history of being inclusive, reasonable, and solid. I think people who badmouth it do so because they don't understand it.
My secret Red Hat sendmail trick. (Score:3, Informative)
These days, Red Hat's default install of sendmail does not accept remote connections. Red Hat tells you to use M4 to generate a new CF file to enable this functionality.
Here is what you really do...
Find the line in the CF file that reads:
O DaemonPortOptions=Name=MTA
and change it to:
O DaemonPortOptions=Port=smtp,Addr=0.0.0.0, Name=MTA
I picked this up from a bugzilla comment.
Re:My secret Red Hat sendmail trick. (Score:2)
DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')
and then make it like this:
dnl DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')
sendmail defaults to listen on every interface, that's why they have to explicitly restrict it to the loopback addr.
Those who don't understand sendmail are doomed... (Score:3, Informative)
...to repeat it.
Um, wait. That didn't come out right.
Sendmail is so bloated that it apparently takes books to get decent performance out of it.
Seriously, a lot of people just don't understand sendmail and how difficult mail routing is. Sendmail is bloated because it tries to solve a very complex problem in an extremely diverse environment.
Postfix was so easy to use, that I went from reading the man pages to a working system in one hour.
Postfix and sendmail are going in two different directions. Sendmail == configurability, postfix == ease of use.
Sendmail is fast. Not because there's a book on performance tuning does it mean the software is slow. Sendmail is probably as fast as anything else out there.
Sendmail is configurable to no end. I run a sendmail setup with virtual domains, lots of address rewrite rules, spam filters. All my virtual users, and alias maps are in LDAP. I modify all my sendmail virtual users, virtual domains, aliases, etc through a PHP website. Try that with other mailers. They support LDAP, but they are no where as configurable as sendmail.
Then try running these mailers on Linux, bsd, solaris, windows, AIX, etc., etc. No OS lock-in.
Sendmail is well documented.
The prevaling mood on /. these days seems to be if it's not brand new, get rid of it. That's unfortunate.
Re:Sendmail tuning? (Score:2)
<rimshot> Isn't that how they all left the factory? </rimshot>
Nice to see M4 (Score:5, Funny)
I'm trying to remember who said this:
Re:Nice to see M4 (Score:3, Insightful)
For example, this snippet from a production server's sendmail.mc will turn on DNS-based spam filtering, enable the use of procmail for local mail delivery, and define a smart host to send email through:
I won't argue that the equivalent sections of sendmail.cf are, well, opaque. However, I've literally never touched sendmail.cf, other than to look at it and thank $DEITY that a much simpler, human-readable configuration system exists.
Re:Nice to see M4 (Score:5, Insightful)
pretty annoying to have to preprocess one's config file.
If I ran the world, sendmail would optionally preprocess
its config file itself. In other words, you'd be able to use
the m4 file directly.
Re:Nice to see M4 (Score:2)
No arguments here. Fortunately, some systems (such as FreeBSD) have scripts to automate the compilation, which eases the burden significantly. I don't have to remember the specific options to m4; I only have to type "make install".
Re:Nice to see M4 (Score:2)
cat
POSSIBLE += $(shell test -f bitdomain && echo bitdomain.db)
POSSIBLE += $(shell test -f uudomain && echo uudomain.db)
POSSIBLE += $(shell test -f genericstable && echo genericstable.db)
all: ${POSSIBLE} virtusertable.db access.db domaintable.db mailertable.db sendmail.cf
virtusertable.db : virtusertable
makemap -f hash $@
(This is Redhat 7.2, and I added the sendmail.mc make myself.)
dave
Re:Nice to see M4 (Score:2)
POSSIBLE += $(shell test -f uudomain && echo uudomain.db)
POSSIBLE += $(shell test -f genericstable && echo genericstable.db)
all: ${POSSIBLE} virtusertable.db access.db domaintable.db mailertable.db sendmail.cf
virtusertable.db : virtusertable
makemap -f hash $@ < $<
userdb.db : userdb
makemap -f hash $@ < $<
%.db : %
makemap hash $@ < $<
clean:
rm -f *.db *~
sendmail.cf: sendmail.mc
m4 sendmail.mc >
(Damn html entities!)
Re:Nice to see M4 (Score:2)
Performance tuning? (Score:3, Funny)
Don't forget... (Score:4, Funny)
Rice-Boy! (Score:2)
Sendmail as Rice-Boy [riceboypage.com] -- what a concept :)
My sendmail.. (Score:2)
.. always needs tuning. The strings need replacing, the wood frame warps in the humidity. It's a real bitch.
What is with all the sendmail bashing? (Score:5, Insightful)
If you like another mail program, DO A BOOK REVIEW ON THAT MAIL PROGRAM and share your "wisdom" with the rest of us.
As for sendmail, it is not meant for Windows weenies or wanna be Unix sysadmins, only for "real" Unix admins and those that wish to use a VERY robust product and are willing to learn the product to reap the rewards. I personally feel that this book is a great quick reference for when you have a brain fart and don't feel like mulling through the O'Reiley "bat-book" for a simple answer
Just my $0.02 cents
Re:What is with all the sendmail bashing? (Score:2)
Cute
Folks, I'm not trolling here
Re:What is with all the sendmail bashing? (Score:2, Redundant)
If I had mod points right now, I would have used them to mod up.
Intelligent post, I think the first one that doesn't bash sendmail. There should be a lot of -1 redundant mods on this one...
Re:What is with all the sendmail bashing? (Score:2)
Though your post overall, does have merit, I'd have to disagree with your arguement. I thought Sendmail was supposed to be an MTA, not an elitist's source of sadomasochism.
When looking for an MTA I first look for something that is secure and something that works best. Then I look for an MTA that offers high performance. Never have I looked for or wanted ANY software package that was unnecessarily complex.
That's a bit like learning assembly for the hell of it, even though you don't have any interest in programming.
Re:What is with all the sendmail bashing? (Score:5, Insightful)
Are you kidding?
I can get PostgreSQL to master/slave replicate a database cluster over 5 servers in faster time that I can get Sendmail do somthing simple. Really.
The Sendamil config files might as well be binary - there useless to human eye. And, no, you shouldent have to learn a line-noise language just for a silly MTA.
Sendmail is just a bitch. I had it's time in the sun, and it's time to move on.
only for "real" Unix admins
A 'real' Unix admin wants to get work done and learn somthing usefull. Managing Sendmail is just memorising a bunch of trivia about it and hoping it works as you think it should. Managing Postfix or Qmail is like managing any other decent Unix server - and by learning one of them you can take that knowlage and use it somewhere else.
A 'real' Unix admin knows when a peice of software is a cobbled peice of crap and when to move on to somthing sane.
Re:What is with all the sendmail bashing? (Score:3, Funny)
I'm looking to do exactly that! How? (I'm not kidding) I'll trade you, you show me the replication trick and I'll show you how to do simple things with sendmail
/
Re:What is with all the sendmail bashing? (Score:2, Informative)
Wrongo here!
I know both qmail and sendmail. With sendmail I can do almost everything I need. With qmail I have to search Internet for bits of information, patches and them write my own patches because of simple-minded approach of qmail author. A lot of corners were cut to make qmail faster - it made it very inconvenient to have it in production environment.
Qmail just lacks flexibility...
Re:It needs to be done (Score:2)
What you describe is sendmail as it existed about 5 years ago. Any reasonably intelligent sysadm could get a simple sendmail config downloaded from the distro site and running in a couple of hours.
The security problems are largely a thing of the past too. Apart from a couple of minor obscure and possibly unexploitable problems (and that embarrassing trojan in the build process), there have been no security problems with sendmail for years.
Sendmail might not be the fastest, but how fast does your mail server have to be? I was able to get eight messages / second out of my G4 powerbook without any tuning whatsoever. This is not really a lot, but otoh represents nearly 30,000 messages per hour. How many do you get every day?
heh (Score:5, Funny)
Spock: K4YM3
Computer: Correct. What was Kiri-kin-tha's first law of metaphysics?
Spock: Nothing unreal exists.
Computer: Correct. Adjust the sine wave of this magnetic envelope so that anti-neutrons can pass through it but anti-gravitons cannot.
Spock: (Spock works keypad and the image of the envelope is changed on one of the screens.)
Computer: Correct. Identify: (an image appears)
Spock: A Klingon mummification glyph from the earliest part of the Zanxthkolt dynasty.
Computer: Correct. Reconfigure the rulesets from this sendmail configuration to first consult a DNS RBL before delivery to local users without using M4.
Spock:
computer: Reconfigure the rulesets from this sendmail configuration to first consult a DNS RBL before delivery to local users without using M4.
Spock:
Spock's Mom: What is it, Spock, what's wrong?
Spock: The question is irrelevant.
Re:heh (Score:2, Insightful)
Tada. (Score:2)
Be sure to maintain LHS/RHS formatting (ie. those aren't spaces)
Inserted after your standard rules in the SBasic_check_relay section
# DNS based RBL bl.spamcop.net
R$* $: $&{client_addr}
R::ffff:$-.$-.$-.$- $: <?> $(host $4.$3.$2.$1.bl.spamcop.net. $: OK $)
R$-.$-.$-.$- $: <?> $(host $4.$3.$2.$1.bl.spamcop.net. $: OK $)
R<?>OK $: OKSOFAR
R<?>$+ $#error $@ 5.7.1 $: Mail from $&{client_addr} rejected; see http://spamcop.net/bl.shtml?$&{client_addr}
Re:Tada. (Score:2)
Exchange Killer (Score:2, Insightful)
No book, but... (Score:2)
Suse OpenExchange [suse.com]
Postfix: Add mine to the list of redundant posts (Score:2)
Far better performance than sendmail for my piddling needs. Why, again, would I want sendmail back, and play around tuning?
Re:Postfix: Add mine to the list of redundant post (Score:2)
(about 300K messages/day), I can tell you that it is
sometimes necessary to tune Postfix too. That's not a
slam on Postfix, by the way -- Wietse Venema would tell
you the same thing.
The Author knows a few things about scalability (Score:4, Informative)
Sendmail books... (Score:5, Informative)
And on a side rant to those who bitch about sendmail, If you don't like it.. don't use it. All of the gripes I've seen about it seem to derive from the posters ignorance on how to set it up. Granted,
sendmail performance tuning (Score:2, Funny)
$ apt-get remove sendmail
$ apt-get install mailer-of-your-choice
$
Improves system security, too.
Don't blame Sendmail... (Score:2)
As with most security [sendmail.org] issues, the Admin who sets it up is as responsible for security [sendmail.org] as the programmers are.
Nice to see a positive review (Score:4, Interesting)
Sendmail (the app, not the company) scales quite nicely if you know what you are doing - I've installed sendmail on a couple of old dual-proc HP's and they handle about 2 million messages a day. Yes, that's right; 2 MILLION. It's a "simple" matter of tuning and knowing the file system.
Don't hack the
And, if another tool works better for you (exim, postfix, qmail) - use it! I don't always recommend sendmail, either.
Bobcat
disclaimer: I used to work for Sendmail, Inc. - my cubicle/cage was about 40 feet from where Nick used to sit...
Best thing I ever did was *de*tune sendmail (Score:5, Informative)
You can run dictionary attacks against domains I handle mail for, but at least it will take you a damn long time! I just wish everybody was doing it. Eventually it would take too long to spam effectively.
Re:Best thing I ever did was *de*tune sendmail (Score:2)
Re:Qmail! (Score:2)
Re:Qmail! (Score:5, Funny)
Re:Qmail! (Score:2)
Re:Qmail! (Score:4, Insightful)
Re:Qmail! (Score:2)
Re:Qmail! (Score:2)
Re:Qmail! (Score:2)
Re:Qmail! (Score:2)
Courier (Score:2)
Yeah, I switched us to Courier recently.
I was running qmail, but then needed an IMAP server. Courier-IMAP was the best for Maildirs. Then I needed a web mail server. Sqwebmail (part of Courier) was the best for Maildirs, and used the same subfolder format.
Then I needed mail filtering, and wanted to use Maildrop because it works well with Maildirs. So I just bit the bullet and installed Courier.
Had some initial issues with configuration setup, but after that it's run pretty smooth. Now I just need to get SpamAssassin installed (need a new version of Perl on the mailserver).
Sendmail scared me off in the mid '90s. Haven't touched a .cf file since.
Re:Courier (Score:2)
Re:Courier (Score:2)
Re:Courier (Score:2)
Actually the mail server is OBSD 3.1. However, the Perl stuff on 3.1 doesn't include all the necessary libraries for SpamAssassin. When I tried installing them using CPAN, there was significant breakage. It could be I was doing something wrong.
Haven't had the time to look into that again.
I'd switch to OBSD 3.2, but the software RAID doesn't seem to work... Maybe now just wait for 3.3. and see how that goes.
Re:Qmail! (Score:2)
Bruce
Re:Qmail! (Score:2)
Re:Qmail! (Score:2)
Re:Qmail! (Score:2)
The fact that you cannot distribute modified versions of it pretty much moves it into the non-Free camp.
Re:Not free? (Score:2)
You mean, like, a version that installs binaries in /var? Oh, wait...
I really don't understand the non-free label attached to Qmail by some people.
You can't change it and restribute the modified version. Without that ability, how is it significantly different than the "freeware" that floated around on BBSes in the 80s and 90s?
Just because something is GNU/Free doesn't mean it's good, and something that doesn't meet the GNU definition of "free" isn't necessarily bad.
First, I never said a thing about GNU - I tend toward BSD, personally. Second, I made no judgement of its relative goodness or badness, which is entirely different from declaring it Free or non-Free. It may very well be a great program, but if it's not Free, then it's not useful for me in my applications.
Re:Qmail! (Score:2)
Although many others in my department, including the main mail server, use postfix.
Re:Qmail! (Score:2)
Re:Qmail! (Score:2)
LDAP is supported out of the box with sendmail, no need to download extra patches and stuff.
Re:Qmail! (Score:2)
--NBVB
Re:Qmail! (Score:2)
Sendmail's not NEARLY the problem it used to be. It's a whole lot better than ever before, and it works out of the can without Dan Bernstein's mess all over it.
Philosophically, I couldn't use software written by such a jerk anyway.
Re:Qmail! (Score:2)
Re:Qmail! (Score:2)
dave
Re:How to improve Sendmail performance. (Score:3, Informative)
Since Sendmail hasn't been monolithic for a couple of versions now, have you considered switching back?
Re:How to improve Sendmail performance. (Score:2)
There are a lot of wannabes going around repeating old news
and thinking they're hip.
Re:How to improve Sendmail performance. (Score:2)
Re:Simply, small, secure. (Score:2)
Re:Sendmail Performance Tuning - the short guide (Score:3, Funny)
Re:Sendmail Performance Tuning - the short guide (Score:2)
LOL! A pity I just wasted my last moderator point on something not half as funny some minutes ago!
Qmail is a little more difficult with Debain, but an qmail-src package exists and works for me.
Re:Sendmail Performance Tuning - the short guide (Score:2)
Better yet, go with a distro [gentoo.org] that doesn't foist Sendmail on you by default...you can then do something like this:
# emerge qmail
Re:I would love to get sendmail running (Score:2)
However, all POP protocols are brain-dead and lame. You should be using IMAP, which is supported by all decent end-user mailers (MUAs, or Mail User Agents) as well as by Microsoft's latest MUAs.
In v5-7.3 RedHats, type ntsysv from the command line and turn on IMAP (or, better yet, IMAPS, if you comprendhez crypto) and SENDMAIL in the runlevel of your preference (I recommend 3, since Xwindows is bloated and unreliable).
If you want an exchange server clone (NOTE: only really useful if you run Outlook, the world's absolute worst MUA for security and reliability, which runs only on proprietary opsystems that have high hardware requirements) use HP Openmail. Or wait for Miguel de Icaza to write something better.
One thing to remember, regardless of what MTA you use, it should NOT relay Email from any address other than 127.0.0.1 unless you specifically configure in the addresses/domains you want to relay from. So you will need to edit
I ran 400 users on redhat5.2+sendmail+ipop3d server and win98+pegasus clients, the clients popped the mail server every 7 seconds, and the server was a pentium 133 with four ethernet cards on it. No performance problems in our real-world shop.
For my users, reliability + performance = ability to generate profit = paychecks for workers. Features that cannot be obtained without sacrificing reliability or price/performance will not be implemented, because the goal is to earn enough to feed the kiddies, not to be 1337.
All that being said, I recommend you install Postfix rather than sendmail. I use sendmail because I already know how to do it, and it works with OpenLDAP. I don't think you fit the profile.
Re:Die Sendmail, die!! (Score:2)
The best tuning is to get rid of that software (which was OK for the 80's, but not for the 21st century)....
You know, I would be angry at you moderators except your mothers are under my desk right now making me happy as I type