On Sat, 5 Jan 91 18:52:04 +0100 Eric Thomas said:
>It's a  problem at  their site,  ie *they* know  how to  fix it  (if they
>don't,  they  should call  the  software  vendor). They  have  apparently
>decided  to restrict  access  to the  internet via  some  exit such  that
>anybody can send but not everybody can receive mail.
 
My understanding of the RFC's is that such a restriction is a distinct
"no-no" under Internet rules (it's probably alright to make some accounts
able to receive only, but return addresses MUST!! be valid).  If the
site is new on the Internet they're probably having difficulty getting
the configuration to work correctly (the problem they had with bunged
MX records seems to indicate they're having some problems).