==== Required information ====
- iRedMail version (check /etc/iredmail-release):
- Linux/BSD distribution name and version:
- Store mail accounts in which backend (LDAP/MySQL/PGSQL):
- Web server (Apache or Nginx):
- Manage mail accounts with iRedAdmin-Pro?
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

CentOS with IredAdmin-Pro on MySQL

date/time host_name postfix/qmgr[1940]: E4C1C400AE8: from=<>, size=12843, nrcpt=1 (queue active)

Have 183 of these. 
What is the queue active part?
    as postqueue -p and mailq both show nothing in queue.

How can one determine how a user is connecting to send an email form a domain NOT on the system?  For example: there is a domain account with a user account and aliases for the domain.  However, they appear to be sending out using their Verizon account according to the general send logs.  How do I locate which account/alias from which their getting the connection?   

Example message
...postfix/qmgr[1940]: 88126439FC4: from=<a_user_account@verizon.net>, size=2887, nrcpt=1 (queue active)