I'm using version 8.05 and the spam filtering capability of that version is becoming ineffective even with the Anti-spam updates. I have put in place a 3rd party spam server proxy which incoming email gets sent through for filtering and then relays to the Imail server. The spam filter does subject modification, so in Imail I use a rule to check for either the X-header from Imail or the modified subject to determine if it should go to spambox or not.
Here's the problem. After changing the MX record, spammers are still sending email directly to the Imail server because they either know it already exists, or their DNS servers cache the old MX record forever. I can't shutoff access to Imail's external IP address, because legitimate users of about 100 domains still go there to send their email and require SMTP access. Solution (in theory): I need an Imail rule which either detects the presence of the spam filter proxy's IP address in the header (easy) or can tell if the email was sent by an authenticated user (impossible, as far as I know). Any email other than those 2 exceptions would be classified as spam because they didn't go through the proper channels. In effect, no email would be received by users by sending it directly to the Imail server. The problem is that users of one domain could not email users of another domain hosted on the same server because they didn't go through the spam proxy, nor can authentication be determined. So, I'm wondering if 1 of 2 options exist: 1. Can authenticated email be identified somehow with a rule? 2. Can an X-header be inserted on outgoing email? Thanks for any ideas! Adam 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/
