A possible answer would be that if a message has multiple recipients, the fact
that one recipient fails or is unknown doesn't mean that the rest shouldn't be
attempted.
I think that if a 500 error occurs, the connecting mail server or mua
discontinues any further delivery of the message.
But
This is not necesarily a courier question, but since thats what i use
What reason is there to respond to a "user unknown" with transient
error code instead of a permanent failure ? ..like this:
: 450 <[EMAIL PROTECTED]>: User unknown in local recipient table
i've seen this a couple of tim
