I created another thread previously, where I reported about the problem that I wasn't able to get saslauthd starting up at all: SMTP authentification: saslauthd won't start
I now re-installed a completely new Ubuntu 16.04 system on my VPS in order to set up postfix with SMTP-SASL authentification from the scratch. At least now "ps ax" shows that saslauthd is running, but it still doesn't work, as a telnet test seems to suggest:
root@servername:~# telnet localhost 25 Trying ::1... Connected to localhost. Escape character is '^]'. 220 servername.com ESMTP Postfix (Ubuntu) EHLO test 250-servername.de 250-PIPELINING 250-SIZE 10240000 250-VRFY 250-ETRN 250-STARTTLS 250-ENHANCEDSTATUSCODES 250-8BITMIME 250-DSN 250 SMTPUTF8
(It should show "250-AUTH LOGIN PLAIN" if it would be working properly).
I've configured smtpd to run in a chroot environment and changed the configuration files accordingly, but also when not running it via chroot (with modified configuration) the result is the same.
The "postfix" user belongs to the "sasl" group and there's no error output in /var/log/mail.log. Also /var/log/auth.log seems to suggest that saslauthd starts without any problems.
I collected all relevant configuration files and output here: postfix and sasl configuration / output
If there's anything else that might be relevant I'll post this as well of course.
I'd be really thankful for any ideas, suggestions or advice, since I've already spent many hours on configuring this, but still can't get the SMTP-SASL authentification running (besides this issue my mail server is running fine).