>What is the root cause of the problem? IMail? server HW? List volume?
A combination of all of the above. :) You can look at http://www.declude.com/dq.htm for an overview of the problem. IMail can only send out about 30 E-mails at a time, and after that, the E-mail gets backed up in the spool, and delivered slowly. IMail's lists are fine for lower volume lists (hundreds of users), but not so good for larger lists (many thousands of users, as this list probably has). The volume also has a big impact on the performance. Of course, our free Declude Queue was designed to make the most of the architecture and get those E-mails out a lot faster (by helping eliminate the cases where 1 process is being used to send outgoing mail when there are thousands of E-mails waiting to be delivered). Ipswitch could also use IMGate as Len mentioned, so the E-mail could quickly be offloaded to a Unix machine which would handle the actual delivery (which would be quicker, because hundreds of E-mails could be sent simultaneously). -Scott --- Declude: Anti-virus, Anti-spam and Anti-hijacking solutions for IMail. http://www.declude.com --- [This E-mail was scanned for viruses by Declude Virus (http://www.declude.com)] Please visit http://www.ipswitch.com/support/mailing-lists.html to be removed from this list. An Archive of this list is available at: http://www.mail-archive.com/imail_forum%40list.ipswitch.com/ Please visit the Knowledge Base for answers to frequently asked questions: http://www.ipswitch.com/support/IMail/
