Adding functionality is not just a matter of adding code.

Defect-free software does not exist.

I was going to visit IBM for six months as a visiting scientist. Now, six months is a lot of time, so I came with a whole list of projects that I might want to work on.

I don't expect an overnight change of all desktops to what the US Military used to call B3 level security. And even that would not stop users from shooting themselves into the foot.

However, writing software without defects is not sufficient. In my experience, it is at least as difficult to write software that is safe - that is, software that behaves reasonably under adverse conditions.

I want to avoid locking people into solutions that work only with Postfix. People should have a choice in what software they want to use with Postfix, be it anti-virus or otherwise.

Qmail out of the box works fine, so people will want to use it regardless of licensing restrictions, even when the software does not ship with their system software.

When I write software, I know that it will fail, either due to my own mistake, or due to some other cause.

The challenge with Postfix, or with any piece of software, is to update software without introducing problems.

Sure, but competition is good for the user.

As of today, the Postfix mail transport agent has almost 50,000 lines of code, comments not included.

Like all software, Qmail can survive only when it keeps up with changing requirements.

Most of the effort in the software business goes into the maintenance of code that already exists.

Coming back to the topic of computer security, the TCP Wrapper is an example of such a safety net. I wrote it when my systems were under attack by someone who appeared to walk through walls.

This will surprise some of your readers, but my primary interest is not with computer security. I am primarily interested in writing software that works as intended.

For many people my software is something that you install and forget. I like to keep it that way.

At the time the Sendmail program had a very poor reputation with respect to security, with four root vulnerabilities per year for two successive years.

One bug in an SMTP server can open up the whole machine for intrusion.

Windows favors multi-threading, which means that a service is implemented by one single process.

Writing software that's safe even in the presence of bugs makes the challenge even more interesting.

Postfix keeps running even if one Postfix process dies; Windows requires that someone restarts the service.

Lack of documentation is becoming a problem for acceptance.

The Postfix security model is based on keeping software simple and stupid.

In a previous life I wrote the software that controlled my physics experiments. That software had to deal with all kinds of possible failures in equipment. That is probably where I learned to rely on multiple safety nets inside and around my systems.

My reply is: the software has no known bugs, therefore it has not been updated.

Adding functionality is not just a matter of adding code.

I've been all over the world on my own because, as a scientist, you travel a great deal if your work is reasonably successful or published. I get invitations to go to all sorts of strange countries where I would mostly be by myself and just meet other people there, instead of having travelling companions.

If thou wilt make a man happy, add not unto his riches but take away from his desires.

Most brands want to see their products used in creative ways.

An idea is salvation by imagination.

Just try to be happy. Unhappiness starts with wanting to be happier.

Human nature is good just as water seeks low ground. There is no man who is not good just as there is no water that does not flow downward.

In any bureaucracy the people devoted to the benefit of the bureaucracy itself always get in control and those dedicated to the goals the bureaucracy is supposed to accomplish have less and less influence and sometimes are eliminated entirely.

I've been around golf my whole life. My father did it all the time, and I resented him for it. But a couple years ago I picked up a golf club and I understood the physics of it. If anyone knows anything about golf, it's that once you hit a few shots, you'll become addicted.

Bringing out your vulnerable side and shedding your privacy in front of complete strangers is so very difficult, but when you are into the performance, the relief and release is so extraordinary that you get addicted.

I like to separate the music- and lyric-writing processes if I can. I'll sort of noodle around on my keyboard and my computer until I have a beat or a chord progression, I'll record it as a loop, export it to iTunes, then walk around with the loop and sort of talk to myself in the loop, and that's how I get the lyrics.

Every accident, no matter how minor, is a failure of the organization.

An invention has to make sense in the world it finishes in, not in the world it started.

You must thank the gods for art, those of us who have been fortunate enough to stumble onto this means of venting our craziness, our meanness, our towering disgust.

Dark economic clouds are dissipating into an emerging blue sky of opportunity.

The country has moved off track. The people in Washington don't have the hard-nosed business experience needed to get the economy up and running.

I wear my heart on my sleeve.

Congress shall make no law respecting an establishment of religion or prohibiting the free exercise thereof.

Friends help you up when you fall. Best friends laugh and trip you again.

I definitely want to do movies and stuff.

As for me, I've been in love with women and men. I get how people fall in love with different kinds of people, but to fall in love with God: I didn't get that.

Some people can be president, some people can speak, some people, you know, anything that's positive, man - a dentist, a doctor. Just hang in there and never give up, and find out what is your talent. First you got to find your talent and just stick with your talent, and I guarantee you'll get there, man.

Spring makes its own statement, so loud and clear that the gardener seems to be only one of the instruments, not the composer.

I'm doing a film called 'Black Mass' where I play James Bulger. The reason to play him is obvious to me. He's a fascinating character. It's not like anything I've done before on that level. I'm very excited to slide into that skin for a little bit.