At 23:21 08/14/2001 Tuesday, Ben Parker wrote:
 >On Tue, 14 Aug 2001 21:56:20 -0400, Tom Rawson <[log in to unmask]> wrote:
 >
 >>Can someone explain how "Last error:  Unavailable" happens and what "DSN"
 >>status means?
 >
 >DSN=Delivery Status Notification (failure/success of message delivery)
 >    RFC 1893/1894

ftp://ftp.isi.edu/in-notes/rfc1893.txt

I'll leave it as an exercise to the reader to find the second mentioned URL ;-)

/Pete