You run Postfix non-chrooted with a MySQL DB as backend.
The issue :
You can’t run Postfix chrooted because the MySQL sock is not located in the chroot area.
**The fix : **
Edit /etc/my.cnf and add this line under the [mysqld] section :
bind-address = 127.0.0.1
Make Postfix connect to MySQL using TCP instead of using sock
Change your SQL files from :
user = username password = password dbname = database hosts = localhost query = SELECT alias FROM batabase WHERE id = '%s'
user = username password = password dbname = database hosts = 127.0.0.1 query = SELECT alias FROM batabase WHERE id = '%s'
By changing the line “hosts” from localhost to “127.0.0.1”, Postfix will use TCP and won’t require access to the sock. That’s the easiest/quickest way of dealing with the problem.
Easily configure Postfix to run chrooted with the script available here : http://blog.wains.be/pub/postfix-chroot