3 things here ..
Thx a lot for your attention!
I've narrowed the problem a bit yesterday evening. It's related to BerkeleyDB. I have wiped out this peace of software (just as a test) and recompiled sendmail from scratch. Now it works, it's listening on 25 as well. I will install BerkeleyDB again more carefully this time and I'll see, how it works.
Originally Posted by BlueC
I would wholeheartedly recommend using postfix as your MTA.
Actually you are the second person recommending this. This is my 1'st mailserver setup attempt and I was in the impression, that sendmail is the leader (which seems not to be true anymore). Because 2 people recommended this, I will consider your suggestion for sure! Anyway, I am also a bit stiffheaded and I don't want to give up so early. I would be very happy to learn sendmail first, so I can also compare those 2 softs.
Again, thx for your time. I really appreciate it!