Welcome!

Linux Containers Authors: Elizabeth White, Pat Romanski, Yeshim Deniz, Liz McMillan, Amit Gupta

Related Topics: Linux Containers

Linux Containers: Article

qmail

Delivering security and performance

In the area of Mail Transfer Agents (MTAs), most people would look at sendmail as the most popular solution in the open source/Linux arena. However, it's not the only solution. Although postfix is popular with a number of administrators (especially those with multiple domains and many users), qmail is the unknown underdog that the experts use.

John Levine, well-known book author and Internet guru, talks about his new book, qmail, which covers the entire gamut of qmail administration from installation to configuration and filtering.

LWM: Another title in the successful mail-management series. Can you tell me the main benefits of qmail over other MTAs such as sendmail?

John Levine: qmail's two strongest points are security and performance. qmail was designed and written by a computer security geek, and is small enough so that if you want, you can read all the source. There's never been a security bug in qmail, that is, one that lets one user damage another's mail or get access to unauthorized parts of the system.

In the kind of environment for which it was designed, with lots of bandwidth, qmail pumps out mail at a phenomenal rate. Dan Bernstein's original motivation for writing qmail was to get mailing list mail delivered fast, and it does that really well.

qmail has always struck me as complex to set up, but easier to manage in the long term. Is that a fair assessment?

It's not so much that it's complex to set up but that it's utterly different from sendmail. The basic configuration is pretty simple, but it's in a bunch of separate files rather than the barococo majesty of sendmail.cf.

The other problem in setting up qmail is due to its peculiar license that doesn't permit people to redistribute modified versions, so you have to pick up the original 1998 code and patch it to add new stuff. Fortunately, earlier this year several members of the qmail community put together netqmail, which combines qmail with a set of widely used patches and it's all you need.

Spam and UBE are obviously big headaches for managers today. What features does qmail support to help combat this?

Nothing built in, but just about every anti-spam scheme you ever heard of is available as a qmail add-on. Dan offers a program called rbldnsd that uses DNS blocklists like the SBL, and people add spam filters such as procmail, greylists, you name it. qmail's modular structure makes it easy to splice new features in.

Do you think there is a solution to spam, or is it something we'll all just have to live with?

There's certainly no magic bullet, but I think that combinations of technical and legal measures will eventually get it under control, although never make it completely go away.

You're a long-time author, well known for a large number of titles and the Internet Gurus group. Can I ask you how you manage the mountains of e-mail you must receive?

It's all standard Unix tools. I use procmail to sort my mail, Pine to read it, and I put most of the mailing lists to local newsgroups so I can read them with trn.

qmail handles a dizzying array of potential delivery and mail routing options. What's the best way to approach a new installation?

Start with a basic installation, then figure out what extra stuff you need. The configuration is mostly driven out of text files so it's easy enough to add new bits to your configuration. You'll also find that once you get some experience with qmail, what you want to add will be more evident.

Migration from an existing setup seems even more complicated. Is there some way of easing the migration from sendmail or postfix?

 Well, there is a chapter in my book on it. You have to figure out what your current setup is doing, then run down the list and make qmail do all the things you care about. I've often found that old sendmail setups have mountains of cruft, and you can throw a lot of it away when you see what your mail system is really doing.

You cover both IMAP and POP in your book. Which do you recommend?

Depends on your usual connection. If it's on a LAN or broadband, IMAP rocks, particularly if you're using one of the Maildir-based IMAP servers (Courier or binc) that supports multiple simultaneous sessions. I can have Pine on my BSD box, Thunderbird on my PC, and Web mail all open at once, and it just works, all viewing the same mailboxes.

On the other hand, if you do dialup, you're still better off with POP since IMAP can be painfully slow over a slow connection.

Could you tell us what we can expect to see from you next?

Internet for Dummies, fabulous all new 10th edition coming next summer.

About John R. Levine

John R. Levine writes, speaks, and consults on the Internet, electronic mail, cybersecurity, and related topics (www.johnlevine.com).

More Stories By Martin C. Brown

Martin C. Brown is a former IT director with experience in cross-platform integration. A keen developer, he has produced dynamic sites for blue-chip customers, including HP and Oracle, and is the technical director of Foodware.net. Now a freelance writer and consultant, MC, as he is better known, works closely with Microsoft as an SME; has a regular column on both ServerWatch.com and IBM's DeveloperWorks Grid Computing site; is a core member of the AnswerSquad.com team; and has written books such as XML Processing with Perl, Python and PHP, and the Microsoft IIS 6 Delta Guide.

Comments (0)

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


@ThingsExpo Stories
SYS-CON Events announced today that Yuasa System will exhibit at the Japan External Trade Organization (JETRO) Pavilion at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Yuasa System is introducing a multi-purpose endurance testing system for flexible displays, OLED devices, flexible substrates, flat cables, and films in smartphones, wearables, automobiles, and healthcare.
SYS-CON Events announced today that Taica will exhibit at the Japan External Trade Organization (JETRO) Pavilion at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Taica manufacturers Alpha-GEL brand silicone components and materials, which maintain outstanding performance over a wide temperature range -40C to +200C. For more information, visit http://www.taica.co.jp/english/.
As hybrid cloud becomes the de-facto standard mode of operation for most enterprises, new challenges arise on how to efficiently and economically share data across environments. In his session at 21st Cloud Expo, Dr. Allon Cohen, VP of Product at Elastifile, will explore new techniques and best practices that help enterprise IT benefit from the advantages of hybrid cloud environments by enabling data availability for both legacy enterprise and cloud-native mission critical applications. By rev...
Organizations do not need a Big Data strategy; they need a business strategy that incorporates Big Data. Most organizations lack a road map for using Big Data to optimize key business processes, deliver a differentiated customer experience, or uncover new business opportunities. They do not understand what’s possible with respect to integrating Big Data into the business model.
Recently, REAN Cloud built a digital concierge for a North Carolina hospital that had observed that most patient call button questions were repetitive. In addition, the paper-based process used to measure patient health metrics was laborious, not in real-time and sometimes error-prone. In their session at 21st Cloud Expo, Sean Finnerty, Executive Director, Practice Lead, Health Care & Life Science at REAN Cloud, and Dr. S.P.T. Krishnan, Principal Architect at REAN Cloud, will discuss how they b...
Enterprises have taken advantage of IoT to achieve important revenue and cost advantages. What is less apparent is how incumbent enterprises operating at scale have, following success with IoT, built analytic, operations management and software development capabilities – ranging from autonomous vehicles to manageable robotics installations. They have embraced these capabilities as if they were Silicon Valley startups. As a result, many firms employ new business models that place enormous impor...
SYS-CON Events announced today that Dasher Technologies will exhibit at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 - Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Dasher Technologies, Inc. ® is a premier IT solution provider that delivers expert technical resources along with trusted account executives to architect and deliver complete IT solutions and services to help our clients execute their goals, plans and objectives. Since 1999, we'v...
SYS-CON Events announced today that MIRAI Inc. will exhibit at the Japan External Trade Organization (JETRO) Pavilion at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. MIRAI Inc. are IT consultants from the public sector whose mission is to solve social issues by technology and innovation and to create a meaningful future for people.
SYS-CON Events announced today that TidalScale, a leading provider of systems and services, will exhibit at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 - Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. TidalScale has been involved in shaping the computing landscape. They've designed, developed and deployed some of the most important and successful systems and services in the history of the computing industry - internet, Ethernet, operating s...
SYS-CON Events announced today that TidalScale will exhibit at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. TidalScale is the leading provider of Software-Defined Servers that bring flexibility to modern data centers by right-sizing servers on the fly to fit any data set or workload. TidalScale’s award-winning inverse hypervisor technology combines multiple commodity servers (including their ass...
Amazon is pursuing new markets and disrupting industries at an incredible pace. Almost every industry seems to be in its crosshairs. Companies and industries that once thought they were safe are now worried about being “Amazoned.”. The new watch word should be “Be afraid. Be very afraid.” In his session 21st Cloud Expo, Chris Kocher, a co-founder of Grey Heron, will address questions such as: What new areas is Amazon disrupting? How are they doing this? Where are they likely to go? What are th...
SYS-CON Events announced today that IBM has been named “Diamond Sponsor” of SYS-CON's 21st Cloud Expo, which will take place on October 31 through November 2nd 2017 at the Santa Clara Convention Center in Santa Clara, California.
Infoblox delivers Actionable Network Intelligence to enterprise, government, and service provider customers around the world. They are the industry leader in DNS, DHCP, and IP address management, the category known as DDI. We empower thousands of organizations to control and secure their networks from the core-enabling them to increase efficiency and visibility, improve customer service, and meet compliance requirements.
Join IBM November 1 at 21st Cloud Expo at the Santa Clara Convention Center in Santa Clara, CA, and learn how IBM Watson can bring cognitive services and AI to intelligent, unmanned systems. Cognitive analysis impacts today’s systems with unparalleled ability that were previously available only to manned, back-end operations. Thanks to cloud processing, IBM Watson can bring cognitive services and AI to intelligent, unmanned systems. Imagine a robot vacuum that becomes your personal assistant tha...
SYS-CON Events announced today that IBM has been named “Diamond Sponsor” of SYS-CON's 21st Cloud Expo, which will take place on October 31 through November 2nd 2017 at the Santa Clara Convention Center in Santa Clara, California.
In his Opening Keynote at 21st Cloud Expo, John Considine, General Manager of IBM Cloud Infrastructure, will lead you through the exciting evolution of the cloud. He'll look at this major disruption from the perspective of technology, business models, and what this means for enterprises of all sizes. John Considine is General Manager of Cloud Infrastructure Services at IBM. In that role he is responsible for leading IBM’s public cloud infrastructure including strategy, development, and offering ...
SYS-CON Events announced today that N3N will exhibit at SYS-CON's @ThingsExpo, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. N3N’s solutions increase the effectiveness of operations and control centers, increase the value of IoT investments, and facilitate real-time operational decision making. N3N enables operations teams with a four dimensional digital “big board” that consolidates real-time live video feeds alongside IoT sensor data a...
In a recent survey, Sumo Logic surveyed 1,500 customers who employ cloud services such as Amazon Web Services (AWS), Microsoft Azure, and Google Cloud Platform (GCP). According to the survey, a quarter of the respondents have already deployed Docker containers and nearly as many (23 percent) are employing the AWS Lambda serverless computing framework. It’s clear: serverless is here to stay. The adoption does come with some needed changes, within both application development and operations. Tha...
SYS-CON Events announced today that Avere Systems, a leading provider of enterprise storage for the hybrid cloud, will exhibit at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 - Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Avere delivers a more modern architectural approach to storage that doesn't require the overprovisioning of storage capacity to achieve performance, overspending on expensive storage media for inactive data or the overbui...
With major technology companies and startups seriously embracing Cloud strategies, now is the perfect time to attend 21st Cloud Expo October 31 - November 2, 2017, at the Santa Clara Convention Center, CA, and June 12-14, 2018, at the Javits Center in New York City, NY, and learn what is going on, contribute to the discussions, and ensure that your enterprise is on the right path to Digital Transformation.