> If I eliminate NDRs completely for invalid addresses, though, then > people who make innocent typing mistakes will not know that their > message did not get through.
If you think about mail flow more completely, you will see this most likely isn't the case. 1. [EMAIL PROTECTED] submits mail to mta.foo.com addressed to [EMAIL PROTECTED] 2. mta.foo.com attempts to relay mail to mx.bar.com: mta.foo.com -> HELO foo.com mx.bar.com <- 250 'Hi, Pleased to meet you' mta.foo.com -> MAIL FROM: <[EMAIL PROTECTED]> mx.bar.com <- 250 'Sender OK' mta.foo.com -> RCPT TO: <[EMAIL PROTECTED]> 3. mx.bar.com queries ldap and finds [EMAIL PROTECTED] invalid mx.bar.com <- 550 #5.5.1 '[EMAIL PROTECTED] doesn't exist' mta.foo.com -> QUIT 4. mta.foo.com sends report to [EMAIL PROTECTED] that message couldn't be delivered A couple cases where there would be no notification... 1. The "typoed" address exists and mail is delivered to a non-intended destination 2. mta.foo.com is broken and doesn't do step 4. In short, not a big concern. ~JasonG -- ~ Ninja Email Security with Cloudmark Spam Engine Gets Image Spam ~ ~ http://www.sunbeltsoftware.com/Ninja ~
