On Mon, 27 Jan 1997 10:03:09 -0500 Terry A Moore said:
>I'd like to figure out if the key to the error is the "MX records will
>cause loop" or the "User unknown" message.  I've never understood the
>MX loop issue.  Perhaps one of the gurus here can enlighten me.
My first  idea is  that lmail.vm.timken.com doesn't  do local  delivery for
it's  name and  tries to  find MX  records for  this name.  In doing  so it
detects that it should  send the mail to very the  host it's just receiving
the mail from.
Second,  I wonder  where  the TWO  recipients come  from.  Wild guess:  the
gateway sees [log in to unmask] and expands to [log in to unmask]
for which it finds an MX to lmail.vm.timken.com. Now it MAY be that this
name  has changed  recently from  lmail.timken.com to  lmail.vm.timken.com.
Unfortunately lmail.timken.com  is not aware  of this change, i.e.  it does
not think it should deliver lmail.vm.timken.com locally - this it looks for
an MX for lmail.vm.timken.com which perhaps  has none and uses a generic MX
which points to the gateway.

Christian