One of our clients has been having problems where whenever an external email has multiple recipients on their domain, each recipients receives it a matching number of times (see below). This only occurs for emails originating from outside the company.
- To: 1 user; 1 email received
- To: 3 users; 3 emails received per user.
- To: 1 user (+1 gmail address); 1 email received per user.
- To: 2 users (+1 gmail address); 2 emails per user (1 email to gmail)
- To: 1 user, CC: 1 user; 2 emails per user
This is an up-to-date Exchange 2003 Server (SP2) on an SBS2003 Server. The Exchange server connects to the MTA via POP. The Exchange databases are not near their capacity. All email scanning is disabled in McAfee.
We have checked with the MTA and only one email is being sent to the Exchange server per user.
I have set up 3 test accounts to eliminate any chance of it being related to rules that have been set up specific to users in either Exchange or Outlook.