smtplib does not send to all recipients

[dccarson at gmail.com]

OK, I've discovered the lost messages, but I'm still slightly confused
as to why they ended up there.  The messages were being delivered to
the local machine, box1.domain.com, even though I was addressing them
to <user>@domain.com.

My past experience with smtp mail has been that if I addressed the
domain explicitly, the mail would not stop at the local machine.  This
is in fact why the 'mail' utility is working.  If I use 'mail' to mail
something to <user> with no domain, it goes to the local machine, as I
would expect, but addressed to <user>@domain.com, it goes to the
corporate server.

So why does smtplib deliver to box1.domain.com?  If the local smtp at
box1.domain.com is configured such that this is correct behavior, I
guess I'd expect the 'mail' utility to do the same thing when handling
address <user>@domain.com.

By the way, the long vs. short usernames was a red herring.  Those with
.forward files were getting their mail.