On 20100816 at 06:26 AM Julian Junge typed...<br><div style="margin-left: 40px;">&gt; option a.) When a mail is send to a closed ticket, the mail bounces, and
 the sender receives a notification that his case is closed and he 
please removes the ticket number from the subject and
sends that mail again.
<br></div><br>You could create a reply directing the user what he/she needs to do.&nbsp; In this case ADMIN | QUEUE | Select Queue then click CHANGE button | Modify Follow-Up Option to reject.<br><br><span style="color: rgb(0, 0, 238);">Create/Modify appropriate Auto-Queue response to respond with the appropriate verbiage.</span><br><br><br><br>On 20100816 at 06:26 AM Julian Junge typed...<br>
<div style="margin-left: 40px;">&gt;option b.) The mail does not bounce but&nbsp; a new case is created and OTRS replaces the ticket number in the subject.
<br></div>
<br><span style="color: rgb(0, 0, 238);">Configure the Follow-up option for the queue - ADMIN | QUEUE | Select Queue then click CHANGE button | Modify Follow-Up Option to New Ticket</span><br><br><span style="color: rgb(0, 0, 238);">Create/Modify appropriate Auto-Response&lt;--&gt;Queue responder to respond with a message indicating the ticket has been opened under a new ticket.<br><br><br><br>I think there are default auto-responses available when you initially configure these options, but customizing the auto-responder is IMO a highly recommended step.<br><br><br></span>