2018-09-24 After 25 years with sendmail there was still something to improve 2 years ago
I still like running sendmail on my own systems. But sendmail evolves with time and my configuration does improve slightly sometimes, such as on the introduction of authenticated smtp with secondary passwords. After the recent upgrades to the home server there is a new mail server with some other new details and suddenly other systems at home could not relay. A bit of searching found Best practice: sendmail and SMTP auth with the right flags for the DAEMON_OPTIONS to only offer authentication on port 587 (submission). I noticed the local systems tried relaying via port 587 so I changed this to port 25 where IP-based relaying is allowed. No idea why I set this up to use the port 587 when I set it up previously. And yes, I checked it, I started with sendmail in 1993, so 25 years of sendmail on port 25. I did start with writing my own sendmail.cf rules but I switched to .mc based configurations.