Click here to close now.




















Welcome!

Linux Containers Authors: Kevin Jackson, Elizabeth White, Pat Romanski, Liz McMillan, Esmeralda Swartz

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
As more and more data is generated from a variety of connected devices, the need to get insights from this data and predict future behavior and trends is increasingly essential for businesses. Real-time stream processing is needed in a variety of different industries such as Manufacturing, Oil and Gas, Automobile, Finance, Online Retail, Smart Grids, and Healthcare. Azure Stream Analytics is a fully managed distributed stream computation service that provides low latency, scalable processing of streaming data in the cloud with an enterprise grade SLA. It features built-in integration with Azur...
A producer of the first smartphones and tablets, presenter Lee M. Williams will talk about how he is now applying his experience in mobile technology to the design and development of the next generation of Environmental and Sustainability Services at ETwater. In his session at @ThingsExpo, Lee Williams, COO of ETwater, will talk about how he is now applying his experience in mobile technology to the design and development of the next generation of Environmental and Sustainability Services at ETwater.
SYS-CON Events announced today that Micron Technology, Inc., a global leader in advanced semiconductor systems, will exhibit at the 17th International Cloud Expo®, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. Micron’s broad portfolio of high-performance memory technologies – including DRAM, NAND and NOR Flash – is the basis for solid state drives, modules, multichip packages and other system solutions. Backed by more than 35 years of technology leadership, Micron's memory solutions enable the world's most innovative computing, consumer,...
SYS-CON Events announced today that Pythian, a global IT services company specializing in helping companies leverage disruptive technologies to optimize revenue-generating systems, has been named “Bronze Sponsor” of SYS-CON's 17th Cloud Expo, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. Founded in 1997, Pythian is a global IT services company that helps companies compete by adopting disruptive technologies such as cloud, Big Data, advanced analytics, and DevOps to advance innovation and increase agility. Specializing in designing, imple...
While many app developers are comfortable building apps for the smartphone, there is a whole new world out there. In his session at @ThingsExpo, Narayan Sainaney, Co-founder and CTO of Mojio, will discuss how the business case for connected car apps is growing and, with open platform companies having already done the heavy lifting, there really is no barrier to entry.
SYS-CON Events announced today that HPM Networks will exhibit at the 17th International Cloud Expo®, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. For 20 years, HPM Networks has been integrating technology solutions that solve complex business challenges. HPM Networks has designed solutions for both SMB and enterprise customers throughout the San Francisco Bay Area.
As more intelligent IoT applications shift into gear, they’re merging into the ever-increasing traffic flow of the Internet. It won’t be long before we experience bottlenecks, as IoT traffic peaks during rush hours. Organizations that are unprepared will find themselves by the side of the road unable to cross back into the fast lane. As billions of new devices begin to communicate and exchange data – will your infrastructure be scalable enough to handle this new interconnected world?
WebRTC has had a real tough three or four years, and so have those working with it. Only a few short years ago, the development world were excited about WebRTC and proclaiming how awesome it was. You might have played with the technology a couple of years ago, only to find the extra infrastructure requirements were painful to implement and poorly documented. This probably left a bitter taste in your mouth, especially when things went wrong.
Through WebRTC, audio and video communications are being embedded more easily than ever into applications, helping carriers, enterprises and independent software vendors deliver greater functionality to their end users. With today’s business world increasingly focused on outcomes, users’ growing calls for ease of use, and businesses craving smarter, tighter integration, what’s the next step in delivering a richer, more immersive experience? That richer, more fully integrated experience comes about through a Communications Platform as a Service which allows for messaging, screen sharing, video...
SYS-CON Events announced today that IceWarp will exhibit at the 17th International Cloud Expo®, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. IceWarp, the leader of cloud and on-premise messaging, delivers secured email, chat, documents, conferencing and collaboration to today's mobile workforce, all in one unified interface
The Internet of Things (IoT) is about the digitization of physical assets including sensors, devices, machines, gateways, and the network. It creates possibilities for significant value creation and new revenue generating business models via data democratization and ubiquitous analytics across IoT networks. The explosion of data in all forms in IoT requires a more robust and broader lens in order to enable smarter timely actions and better outcomes. Business operations become the key driver of IoT applications and projects. Business operations, IT, and data scientists need advanced analytics t...
With the proliferation of connected devices underpinning new Internet of Things systems, Brandon Schulz, Director of Luxoft IoT – Retail, will be looking at the transformation of the retail customer experience in brick and mortar stores in his session at @ThingsExpo. Questions he will address include: Will beacons drop to the wayside like QR codes, or be a proximity-based profit driver? How will the customer experience change in stores of all types when everything can be instrumented and analyzed? As an area of investment, how might a retail company move towards an innovation methodolo...
Too often with compelling new technologies market participants become overly enamored with that attractiveness of the technology and neglect underlying business drivers. This tendency, what some call the “newest shiny object syndrome,” is understandable given that virtually all of us are heavily engaged in technology. But it is also mistaken. Without concrete business cases driving its deployment, IoT, like many other technologies before it, will fade into obscurity.
Consumer IoT applications provide data about the user that just doesn’t exist in traditional PC or mobile web applications. This rich data, or “context,” enables the highly personalized consumer experiences that characterize many consumer IoT apps. This same data is also providing brands with unprecedented insight into how their connected products are being used, while, at the same time, powering highly targeted engagement and marketing opportunities. In his session at @ThingsExpo, Nathan Treloar, President and COO of Bebaio, will explore examples of brands transforming their businesses by t...
Akana has announced the availability of the new Akana Healthcare Solution. The API-driven solution helps healthcare organizations accelerate their transition to being secure, digitally interoperable businesses. It leverages the Health Level Seven International Fast Healthcare Interoperability Resources (HL7 FHIR) standard to enable broader business use of medical data. Akana developed the Healthcare Solution in response to healthcare businesses that want to increase electronic, multi-device access to health records while reducing operating costs and complying with government regulations.
For IoT to grow as quickly as analyst firms’ project, a lot is going to fall on developers to quickly bring applications to market. But the lack of a standard development platform threatens to slow growth and make application development more time consuming and costly, much like we’ve seen in the mobile space. In his session at @ThingsExpo, Mike Weiner, Product Manager of the Omega DevCloud with KORE Telematics Inc., discussed the evolving requirements for developers as IoT matures and conducted a live demonstration of how quickly application development can happen when the need to comply wit...
The Internet of Everything (IoE) brings together people, process, data and things to make networked connections more relevant and valuable than ever before – transforming information into knowledge and knowledge into wisdom. IoE creates new capabilities, richer experiences, and unprecedented opportunities to improve business and government operations, decision making and mission support capabilities.
Explosive growth in connected devices. Enormous amounts of data for collection and analysis. Critical use of data for split-second decision making and actionable information. All three are factors in making the Internet of Things a reality. Yet, any one factor would have an IT organization pondering its infrastructure strategy. How should your organization enhance its IT framework to enable an Internet of Things implementation? In his session at @ThingsExpo, James Kirkland, Red Hat's Chief Architect for the Internet of Things and Intelligent Systems, described how to revolutionize your archit...
MuleSoft has announced the findings of its 2015 Connectivity Benchmark Report on the adoption and business impact of APIs. The findings suggest traditional businesses are quickly evolving into "composable enterprises" built out of hundreds of connected software services, applications and devices. Most are embracing the Internet of Things (IoT) and microservices technologies like Docker. A majority are integrating wearables, like smart watches, and more than half plan to generate revenue with APIs within the next year.
Growth hacking is common for startups to make unheard-of progress in building their business. Career Hacks can help Geek Girls and those who support them (yes, that's you too, Dad!) to excel in this typically male-dominated world. Get ready to learn the facts: Is there a bias against women in the tech / developer communities? Why are women 50% of the workforce, but hold only 24% of the STEM or IT positions? Some beginnings of what to do about it! In her Opening Keynote at 16th Cloud Expo, Sandy Carter, IBM General Manager Cloud Ecosystem and Developers, and a Social Business Evangelist, d...