Postfix intermittent lookup failures

Solution 1:

I have configured postfix+Dovecot+MySQL+postfixAdmin+roundcub+ClamAV+amavis.. on CentOS.

When I try to use postfixAdmin to create virtual domain and users, it is so slow, then the following error occurs

"Invalid query: MySQL server has gone away".

Steps to attempt:

  1. Change /etc/my.cnf argument into wait_timeout=28800 (it is default)
  2. Disable name resolve skip-name-resolve
  3. Try editing $CONF['emailcheck_resolve_domain'] to NO in config.inc.php and try again.