Defect-free software does not exist. Wietse Venema More Quotes by Wietse Venema More Quotes From Wietse Venema 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. Wietse Venema experience safe writing Most of the effort in the software business goes into the maintenance of code that already exists. Wietse Venema maintenance effort business Sure, but competition is good for the user. Wietse Venema users competition Like all software, Qmail can survive only when it keeps up with changing requirements. Wietse Venema requirements software My reply is: the software has no known bugs, therefore it has not been updated. Wietse Venema known bugs software One bug in an SMTP server can open up the whole machine for intrusion. Wietse Venema intrusion machines bugs Postfix keeps running even if one Postfix process dies; Windows requires that someone restarts the service. Wietse Venema process running window 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. Wietse Venema use doe people The Postfix security model is based on keeping software simple and stupid. Wietse Venema software simple stupid The challenge with Postfix, or with any piece of software, is to update software without introducing problems. Wietse Venema updates pieces challenges Windows favors multi-threading, which means that a service is implemented by one single process. Wietse Venema favors mean window Writing software that's safe even in the presence of bugs makes the challenge even more interesting. Wietse Venema challenges writing interesting As of today, the Postfix mail transport agent has almost 50,000 lines of code, comments not included. Wietse Venema agents lines mail 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. Wietse Venema choices should-have people When I write software, I know that it will fail, either due to my own mistake, or due to some other cause. Wietse Venema causes mistake writing Lack of documentation is becoming a problem for acceptance. Wietse Venema documentation becoming acceptance 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. Wietse Venema change military feet 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. Wietse Venema wall safety example 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. Wietse Venema computer surprise writing 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. Wietse Venema respect two years
