Terry and I eventually gave up on this Sendmail book—too hard—and had to bring in a consultant on a colleague’s payroll.
@tejr do you have an academic or commercial interest in Sendmail? I recall, back around 2000, we brought in an external Sendmail specialist (my CF skills were fairly weak) to help integrate a legacy Data General system (used by the health sector) with a modern Postfix server via UUCP... was surprisingly painful to get right... but then it worked flawlessly for a decade +...
@lightweight I’ve never had to implement Sendmail. I’m a Postfix babby, so the most I’ve had to do is fight with its compatibility mode with its /usr/lib/sendmail compatibility interface. Hearing some war stories, I feel like I was fortunate.
@tejr the first commercial email systems I ran were Sendmail, moving quickly to Qmail (due to the complexity of tweaking anything Sendmail) which had to be compiled constantly due to being developed by Daniel J Bernstein... (Also ran DJBDNS, for my sins) and eventually, with a huge sigh of relief, Postfix came onto the scene. Still running it these days, mostly wrapped up in Mailcow Dockerized... a superb solution.
"I appreciate SDF but it's a general-purpose server and the name doesn't make it obvious that it's about art." - Eugen Rochko