Am Freitag, den 29.07.2005, 17:21 +0200 schrieb Eric Thomas:
[...]
> perfectly good reasons? That MX server does not know what addresses exist at
> the other server and cannot answer in-line. Either way, the only difference
There are many, many ways how a MX-server can know what addresses exist
at the servers it is responsible for. If you are not able to install a
MX-server that does only accept valid addresses, you should not operate
an MX-server at all.

However, even if you MX-server has the information, which addresses are
basically valid, legitimate bounces can be created. For example, the
address is valid, but over mail-quota. Or the address is forwarding to
some other address, wich is unreachable, disabled, over quota, etc.

--
CU,
   Patrick.