Just for future reference, the apt-cache command displays available
packages, not installed packages. To check installed packages, use
dpkg -l "package name"
If you don't know the exact package name, use
dpkg -l | grep -i 'package name'
(no output means there are no matching packages)
That said, Postfix seems to be running, so we should probably look at authentication mechanisms next.
Which "Perfect Server" tutorial did you follow? This one? http://www.howtoforge.com/perfect-se...ot-ispconfig-3
All of these log messages are abnormal, too:
pop3d: Maximum connection limit reached for ::ffff:18.104.22.168
I assume that none of those IP addresses are yours, either, correct?
This looks like a Postfix configuration problem. Please post the contents of /etc/postfix/main.cf
, and be sure to wrap it in code tags.