ISPConfig and OpenVZ

Additional Port 81 is reachable from outside:

error.log

http://localhost:81 works

and

https://localhost:81 works, too

http://<ip>:81

generates the error from error log above (error 400) and

https://<ip>:81 results in a not avaialbe page without any error

access.log

Same result when using domain-name instead of IP

Now I have deleted standard virtual apache and removed Listen port 81 from /etc/apache2/ports.

Then I was following the article:

Now it works and all is accessable.