Jul 3 13:06:11 mail postfix/error: 9D0E21E40CAF: to=<firstname.lastname@example.org>, relay=none, delay=0.17, delays=0.17/0/0/0, dsn=4.4.1, status=deferred (delivery temporarily suspended: connect to 127.0.0.1[127.0.0.1]:10024: Connection refused)
there's your little bugger .. is amavisd running? :P
ls -al | grep :10024
should give you something like:
tcp 0 0 127.0.0.1:10024 0.0.0.0:* LISTEN 11519/amavisd (mast
you're 2nd question i cannot answer because i run powerdns on 3 completely different ns servers, i don't use the dns service ispconfig can provide me.