Welcome!

Linux Containers Authors: Pat Romanski, Christopher Keene, Roger Strukhoff, Craig Lowell, Liz McMillan

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
Today we can collect lots and lots of performance data. We build beautiful dashboards and even have fancy query languages to access and transform the data. Still performance data is a secret language only a couple of people understand. The more business becomes digital the more stakeholders are interested in this data including how it relates to business. Some of these people have never used a monitoring tool before. They have a question on their mind like “How is my application doing” but no id...
SYS-CON Events announced today that Venafi, the Immune System for the Internet™ and the leading provider of Next Generation Trust Protection, will exhibit at @DevOpsSummit at 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Venafi is the Immune System for the Internet™ that protects the foundation of all cybersecurity – cryptographic keys and digital certificates – so they can’t be misused by bad guys in attacks...
Pulzze Systems was happy to participate in such a premier event and thankful to be receiving the winning investment and global network support from G-Startup Worldwide. It is an exciting time for Pulzze to showcase the effectiveness of innovative technologies and enable them to make the world smarter and better. The reputable contest is held to identify promising startups around the globe that are assured to change the world through their innovative products and disruptive technologies. There w...
SYS-CON Events announced today Telecom Reseller has been named “Media Sponsor” of SYS-CON's 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Telecom Reseller reports on Unified Communications, UCaaS, BPaaS for enterprise and SMBs. They report extensively on both customer premises based solutions such as IP-PBX as well as cloud based and hosted platforms.
Smart Cities are here to stay, but for their promise to be delivered, the data they produce must not be put in new siloes. In his session at @ThingsExpo, Mathias Herberts, Co-founder and CTO of Cityzen Data, will deep dive into best practices that will ensure a successful smart city journey.
The 19th International Cloud Expo has announced that its Call for Papers is open. Cloud Expo, to be held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, brings together Cloud Computing, Big Data, Internet of Things, DevOps, Digital Transformation, Microservices and WebRTC to one location. With cloud computing driving a higher percentage of enterprise IT budgets every year, it becomes increasingly important to plant your flag in this fast-expanding business opportuni...
DevOps at Cloud Expo, taking place Nov 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with 19th Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. The widespread success of cloud computing is driving the DevOps revolution in enterprise IT. Now as never before, development teams must communicate and collaborate in a dynamic, 24/7/365 environment. There is no time to wait for long dev...
In today's uber-connected, consumer-centric, cloud-enabled, insights-driven, multi-device, global world, the focus of solutions has shifted from the product that is sold to the person who is buying the product or service. Enterprises have rebranded their business around the consumers of their products. The buyer is the person and the focus is not on the offering. The person is connected through multiple devices, wearables, at home, on the road, and in multiple locations, sometimes simultaneously...
Internet of @ThingsExpo, taking place November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with 19th Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. The Internet of Things (IoT) is the most profound change in personal and enterprise IT since the creation of the Worldwide Web more than 20 years ago. All major researchers estimate there will be tens of billions devices - comp...
For basic one-to-one voice or video calling solutions, WebRTC has proven to be a very powerful technology. Although WebRTC’s core functionality is to provide secure, real-time p2p media streaming, leveraging native platform features and server-side components brings up new communication capabilities for web and native mobile applications, allowing for advanced multi-user use cases such as video broadcasting, conferencing, and media recording.
Data is the fuel that drives the machine learning algorithmic engines and ultimately provides the business value. In his session at Cloud Expo, Ed Featherston, a director and senior enterprise architect at Collaborative Consulting, will discuss the key considerations around quality, volume, timeliness, and pedigree that must be dealt with in order to properly fuel that engine.
SYS-CON Events announced today that 910Telecom will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Housed in the classic Denver Gas & Electric Building, 910 15th St., 910Telecom is a carrier-neutral telecom hotel located in the heart of Denver. Adjacent to CenturyLink, AT&T, and Denver Main, 910Telecom offers connectivity to all major carriers, Internet service providers, Internet backbones and ...
Amazon has gradually rolled out parts of its IoT offerings in the last year, but these are just the tip of the iceberg. In addition to optimizing their back-end AWS offerings, Amazon is laying the ground work to be a major force in IoT – especially in the connected home and office. Amazon is extending its reach by building on its dominant Cloud IoT platform, its Dash Button strategy, recently announced Replenishment Services, the Echo/Alexa voice recognition control platform, the 6-7 strategic...
19th Cloud Expo, taking place November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, will feature technical sessions from a rock star conference faculty and the leading industry players in the world. Cloud computing is now being embraced by a majority of enterprises of all sizes. Yesterday's debate about public vs. private has transformed into the reality of hybrid cloud: a recent survey shows that 74% of enterprises have a hybrid cloud strategy. Meanwhile, 94% of enterpri...
Akana has announced the availability of version 8 of its API Management solution. The Akana Platform provides an end-to-end API Management solution for designing, implementing, securing, managing, monitoring, and publishing APIs. It is available as a SaaS platform, on-premises, and as a hybrid deployment. Version 8 introduces a lot of new functionality, all aimed at offering customers the richest API Management capabilities in a way that is easier than ever for API and app developers to use.
Personalization has long been the holy grail of marketing. Simply stated, communicate the most relevant offer to the right person and you will increase sales. To achieve this, you must understand the individual. Consequently, digital marketers developed many ways to gather and leverage customer information to deliver targeted experiences. In his session at @ThingsExpo, Lou Casal, Founder and Principal Consultant at Practicala, discussed how the Internet of Things (IoT) has accelerated our abil...
With so much going on in this space you could be forgiven for thinking you were always working with yesterday’s technologies. So much change, so quickly. What do you do if you have to build a solution from the ground up that is expected to live in the field for at least 5-10 years? This is the challenge we faced when we looked to refresh our existing 10-year-old custom hardware stack to measure the fullness of trash cans and compactors.
The emerging Internet of Everything creates tremendous new opportunities for customer engagement and business model innovation. However, enterprises must overcome a number of critical challenges to bring these new solutions to market. In his session at @ThingsExpo, Michael Martin, CTO/CIO at nfrastructure, outlined these key challenges and recommended approaches for overcoming them to achieve speed and agility in the design, development and implementation of Internet of Everything solutions wi...
Cloud computing is being adopted in one form or another by 94% of enterprises today. Tens of billions of new devices are being connected to The Internet of Things. And Big Data is driving this bus. An exponential increase is expected in the amount of information being processed, managed, analyzed, and acted upon by enterprise IT. This amazing is not part of some distant future - it is happening today. One report shows a 650% increase in enterprise data by 2020. Other estimates are even higher....
I wanted to gather all of my Internet of Things (IOT) blogs into a single blog (that I could later use with my University of San Francisco (USF) Big Data “MBA” course). However as I started to pull these blogs together, I realized that my IOT discussion lacked a vision; it lacked an end point towards which an organization could drive their IOT envisioning, proof of value, app dev, data engineering and data science efforts. And I think that the IOT end point is really quite simple…