IMO, the best idea isn't to tell them there's a limit, but simply to bit-bucket any requests that come in under your threshold without POPping the real inbox. We modified IMail to do this back in 1999 or 2000. The design was that within <n> minutes of the last real check, any request would seemingly be allowed (that is, the user would be allowed to authenticate), but the mailbox checked would be a dummy, stored in RAM, that returned the same UIDL as the last time (thus interpreted by the client as "no new messages"). After <n> minutes, the check was allowed to pass through to the actual mailbox on disk and pass actual message data over the wire. The overall effect was to decrease CPU and disk I/O substantially, especially with <n> >= 10.
Around that same time, we also wrote an experimental plug-in for IMail that could trigger Outlook (on remote clients) to run a Send/Receive whenever a message was delivered to the inbox, in near-real-time. It worked, but the problem was that there was still no way to prevent users from _also_ running their own S/R checks whenever they wanted (unless you were in an AD domain, of course). That restriction, together with the fact that only Outlook could be supported, meant that you had to implement the solution in the first paragraph, either way. So we ceased development of the latter software, cool though it was. Per my own intimate observation of the problem, checking once per minute, with the very busy server we were working on back then, can have very bad results for the client and the server. The question becomes whether to silently control the frequency, send explicit warnings, or scale your server farm up and out to handle the extra demand. Budget and your corporate "personality" dictates which one you choose. --Sandy ------------------------------------ Sanford Whiteman, Chief Technologist Broadleaf Systems, a division of Cypress Integrated Systems, Inc. e-mail: [EMAIL PROTECTED] SpamAssassin plugs into Declude! http://www.imprimia.com/products/software/freeutils/SPAMC32/download/release/ Defuse Dictionary Attacks: Turn Exchange or IMail mailboxes into IMail Aliases! http://www.imprimia.com/products/software/freeutils/exchange2aliases/download/release/ http://www.imprimia.com/products/software/freeutils/ldap2aliases/download/release/ To Unsubscribe: http://www.ipswitch.com/support/mailing-lists.html List Archive: http://www.mail-archive.com/imail_forum%40list.ipswitch.com/ Knowledge Base/FAQ: http://www.ipswitch.com/support/IMail/
