In zabbix_server.conf i see:

1. Database host name
2. Default is localhost
   #
3. DBHost=localhost

When i try to start daemon, i see error in log:

1674:20120427:120043.412 [Z3001] connection to database 'mon3' failed: [0] could not connect to server: Permission denied
Is the server running locally and accepting
connections on Unix domain socket "/var/run/postgresql/.s.PGSQL.5432"?

1674:20120427:120043.412 Database is down. Reconnecting in 10 seconds.

When i uncomment DBHost=localhost it's work fine. But why zabbix developers write this "# Default is localhost" if it not true and server can't work with default value of directive?