I have built a similar architecture and have three things to say in response:
1) The... >file that contains a list of all the lists that we have to write to ...is not necessary to send mail to lists. You don't need to update LISTS.TXT unless a) you're interested in presenting your list names via IMAILSRV's LIST command or b) you absolutely, positively, must use this file (and--hint--not a multi-user database) to present an accurate "list of lists" via the native Imail web admin interface (not--another hint!--via a page gen'd by your proprietary app). 2) You *do*, however, need to be able to add your lists' program aliases to the Imail Registry, though I presume you already have this functionality via VBScript or are using the command-line ADDLIST. Luckily, the Reg is sufficiently multi-user. 3) Be attentive to concurrency issues when writing out the USERS.LST file. Yes, it *seems* like only one user will be writing to each file, but what if that same user is logged in twice...control for this in your code or it may be a problem. Time out the file open to make sure it gets closed if a session times out. Also, open it as shareable read write when updating it, so it can also be opened simultaneously for reading by the IMAILSRV process if necessary. Contrary to what Todd suggested, I see no reason not to do this on Imail. You haven't told us how many users you expect per list, but if each one is just one person's legitimate "opt-in" contact list, I can't see it being a problem, given sufficient server hardware. He's certainly right that with big public lists, Imail's not up to the task performance-wise. Of course, that's why we (Broadleaf Systems) are writing a substitute (see my other post)! But until then (he said humbly) the native server will probably do you fine. Regards, Sandy 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/
