Originally Posted by m.xander
So after a new domain is added will I have to change vmail permissions for newdomain.com folder and /var/www/clients/client*/web*/ - I assumed that ISPConfig sets permissions when creating domains, mailbox's, FTP-user's, sites etc. so that the client has the relevant permissions..?
No, you should not have to change permissions on anything. ISPConfig may not set its own permissions, but at a minimum, files and directories that it creates will inherit the permissions of the parent directory. As long as the permissions for the relevant Web, FTP, and mail directories are configured properly from the beginning, they should never have to be changed.
That said, if the software is changed (e.g., replaced, reinstalled, or reconfigured), there's no guarantee that the permissions will continue to be correct.
Well, keep an eye on those logs if any problems arise and holler if this type of thing persists.
As a final point of note, I would remove Postfix and Maildrop altogether, to ensure that they aren't messing with your permissions. If you remove the software, there is the risk of removing packages on which other software depends, so use caution. As long as all of your software was installed using your Linux distributions' packages, the dependencies should be handled automatically.