Re: Received: from a domain without a website?

[Steve Prior]

You're still not quite understanding what I'm talking about, but John Hodson did 
and claims an example which would kill the idea (assuming he's not hosting
spammers that is).  I wasn't talking about a domain that was non-existant, I
was questioning how many domains you would want sending you email that have
email set up but no web service whatsoever.  My theory was that most legit
companies on the web would have web if they had email.

Gary Smith wrote:
I missunderstood Steve's prior question.  If the email comes from a non-existant  domain (that is one that isn't registered with a registrar) then you can 
filter this at the MTA level.  In postfix the setting is 
"reject_unknown_sender_domain".  Your MTA might vary.
 
This doesn't depend upon a www or any other name actually pointing to a server.  The existance of the domain with the registrar and an MX record qualifies it as a valid domain.
 
My opinion is that you should drop this at the MTA level as only spammers of people with really badly configured emails servers do not send email with a fully qualified and valid domain.  But that's my $0.02.
 
Gary Smith