Paul Cocker wrote:
But isn't recipient maps purely checking the destination address to see if it's valid? If so, why does it matter when you check the validity so long as you do before it reaches its final destination for that domain and is bounced?
if your secondary accepts a message to an invalid recipient, what do you think will happen at the end of the journey? your primary will reject your secondary and your secondary will generate a bounce. and how do we call this? backscatter.
it's as simple as this: if one of your servers doesn't reject a mail, you'll have to do something with that mail. if you discard it, you break email reliability (people do mistype addresses sometimes). if you bounce it, you will annoy the rest of us (because you can't prove the sender isn't forged).
