Agreed. Having had the opportunity to encounter, use, setup, and then later on, read the code and learn from qmail early on in my computer career I think it hel

Agreed. Having had the opportunity to encounter, use, setup, and then later on, read the code and learn from qmail early on in my computer career I think it helped learn about proper system design with an eye towards security. Back when qmail was released there was nothing like it, the most popular MTA at the time was Sendmail and we all know how great that was :) qmail had a great impact on system design for many years and especially in the mail delivery area. Things like Maildir redefined how even MUAs store and use email. djbdns also provided a breath of fresh air at the time it was released, worked much faster and much more secure than something like bind. DJB also had many other (likely even more impactful) roles in the software industry, leading the fight against the encryption software export restrictions of the 90s. https://en.wikipedia.org/wiki/Daniel_J._Bernstein https://en.wikipedia.org/wiki/Daniel_J._Bernstein