Can I keep users from receiving mail from the Internet?

[Paul Michael Reilly]

Simon Windsor wrote:
> Fedora wrote:
> 
>> I'm using sendmail as the MTA and I would like to make it impossible for
>> certain users (root comes to mind, but there are other userids as 
>> well) to
>> receive email from the Internet.
>>
>> I'd like to "block" it, as opposed to having some sort of filter throw it
>> away after it's arrived.  Ideally, these few userids would appear to be
>> invalid to anyone outside my network.
>>
>> On the other hand ... I do need for all users to be able to receive email
>> "internally" (i.e., from localhost).
>>
>> In my case, spammers have discovered that there is <gasp!> a "root" user
>> that they can send email to.
>>
>> Any thoughts?
>>
>> Thanks much,
>> Charlie
>>
>>  
>>
> Hi
> 
> A solution to this may be to use forward files.

Can you elaborate or provide a reference?  I don't see how .forward 
files provide a solution.

Thanks,

-pmr